CN1886528A - High-strength and high-toughness magnesium alloy and manufacturing method thereof - Google Patents

Abstract

The present invention provides a high-strength high-toughness magnesium alloy having strength and toughness at a level that can be practically used, and a method for producing the same, aiming at expanding the use of magnesium alloys. The high-strength and high-toughness magnesium alloy according to the present invention is characterized by producing a magnesium alloy cast product containing a atomic% of Zn, b atomic% in total of at least one element selected from the group consisting of Dy, Ho and Er, and the balance of Mg, a and b satisfying the following formulas (1) to (3), and the plastic worked product obtained by plastically working the magnesium alloy cast product has a hcp-structure magnesium phase and a long-period stacking structure phase at normal temperature. (1) A is more than or equal to 0.2 and less than or equal to 5.0, (2) b is more than or equal to 0.2 and less than or equal to 5.0, and (3) b is more than or equal to 0.5a and less than or equal to 0.5.

Description

High-strength and high-toughness magnesium alloy and manufacturing method thereof

technical field

The present invention relates to a high-strength, high-toughness magnesium alloy and a manufacturing method thereof, and more specifically, to a high-strength, high-toughness magnesium alloy that achieves high strength and high toughness by containing a specific rare earth element in a specific ratio, and a manufacturing method thereof.

Background technique

Magnesium alloys are rapidly becoming popular as housings for mobile phones and notebook personal computers and parts for automobiles due to their recyclability.

In order to be able to be used in these applications, high strength and high toughness are required for magnesium alloys. In order to produce high-strength and high-toughness magnesium alloys, various studies have been conducted in terms of materials and production methods.

In terms of manufacturing method, in order to promote nano crystallization, the rapid solidification powder metallurgy (RS-P/M) method was developed, which can obtain a magnesium alloy with a strength of about 400 MPa which is about twice that of the cast material.

As magnesium alloys, Mg-Al type, Mg-Al-Zn type, Mg-Th-Zn type, Mg-Th-Zn-Zr type, Mg-Zn-Zr type, Mg-Zn-Zr-RE ( Alloys with composition systems such as rare earth elements). Even if magnesium alloys having these compositions are produced by casting, sufficient strength cannot be obtained. When the magnesium alloy having the composition described above is manufactured by the RS-P/M method, although higher strength can be achieved compared with the case of manufacturing by the casting method, the strength is still insufficient, or even if the strength is sufficient, the toughness ( Ductility) is also not sufficient, so it has a disadvantage that it is difficult to use in applications requiring high strength and high toughness.

Mg—Zn—RE (rare earth element) alloys have been proposed as magnesium alloys having high strength and high toughness (for example, Patent Documents 1, 2, and 3).

Patent Document 1: Patent No. 3238516 (FIG. 1)

Patent Document 2: Patent No. 2807374

Patent Document 3: Japanese Unexamined Patent Publication No. 2002-256370 (Scope of Claims, Examples)

However, in conventional Mg-Zn-RE-based alloys, for example, an alloy material having an amorphous shape is heat-treated to undergo fine crystallization to obtain a high-strength magnesium alloy. In this way, in order to obtain the above-mentioned amorphous alloy material, there is a preconceived notion that a considerable amount of zinc and rare earth elements is required, and a magnesium alloy containing relatively large amounts of zinc and rare earth elements is used.

Although patent documents 1 and 2 describe that high strength and high toughness can be obtained, there is basically no alloy that actually has both strength and toughness at a practical level. In addition, the use of magnesium alloys has been expanded at present, and conventional strength and toughness are not sufficient, and magnesium alloys having higher strength and toughness are required.

Contents of the invention

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a high-strength, high-toughness magnesium alloy having a practical level of strength and toughness for the expanded applications of magnesium alloys, and a method for producing the same .

In order to solve the above-mentioned problems, the high-strength and high-toughness magnesium alloy of the present invention is characterized in that it contains Zn at a atomic % and at least one selected from the group consisting of Dy, Ho, and Er at a total of b atomic %. element, the remainder is composed of Mg, and a and b satisfy the following formulas (1) to (3).

(1) 0.2≤a≤5.0

(2) 0.2≤b≤5.0

(3) 0.5a-0.5≤b

Furthermore, each of Dy, Ho, and Er is a rare earth element that forms a crystal structure of a long-period laminated structure phase in a magnesium alloy cast product.

The high-strength and high-toughness magnesium alloy of the present invention is characterized in that it contains a atomic % of Zn, a total of b atomic % of at least one element selected from the group consisting of Dy, Ho, and Er, and the remainder is composed of Mg. , a and b satisfy the following formulas (1) to (3).

(1) 0.2≤a≤3.0

(2) 0.2≤b≤5.0

(3) 2a-3≤b

In addition, the high-strength and high-toughness magnesium alloy is preferably a magnesium alloy cast material subjected to plastic working.

The high-strength and high-toughness magnesium alloy of the present invention is characterized in that the following magnesium alloy castings are produced, and the plastic processed products after plastic working of the magnesium alloy castings have a hcp structure magnesium phase and a long period of time at room temperature. A laminated structure phase, wherein the magnesium alloy casting contains a atomic % of Zn, a total of b atomic % of at least one element selected from the group consisting of Dy, Ho, and Er, and the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3),

(1) 0.2≤a≤5.0

(2) 0.2≤b≤5.0

(3) 0.5a-0.5≤b

The high-strength and high-toughness magnesium alloy of the present invention is characterized in that a magnesium alloy casting containing a atomic % of Zn and a total of b atomic % of Zn selected from the group consisting of Dy, Ho, and Er is produced. At least one element, the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3), and the plastically processed product after plastic processing the magnesium alloy casting has a hcp structure at room temperature Magnesium phase and long-period stacked structure phase.

(1) 0.2≤a≤3.0

(2) 0.2≤b≤5.0

(3) 2a-3≤b

The high-strength and high-toughness magnesium alloy of the present invention is characterized in that a magnesium alloy casting containing a atomic % of Zn and a total of b atomic % of Zn selected from the group consisting of Dy, Ho, and Er is produced. At least one element, the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3), plastic processing is performed on the magnesium alloy casting to produce a plastic processed product, and the plastic processed product is The heat-treated plastic processed product has a hcp structure magnesium phase and a long-period laminated structure phase at room temperature.

(1) 0.2≤a≤5.0

(2) 0.2≤b≤5.0

(3) 0.5a-0.5≤b

The high-strength and high-toughness magnesium alloy of the present invention is characterized in that a magnesium alloy casting containing a atomic % of Zn and a total of b atomic % of Zn selected from the group consisting of Dy, Ho, and Er is produced. At least one element, the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3), plastic processing is performed on the magnesium alloy casting to produce a plastic processed product, and the plastic processed product is The heat-treated plastic processed product has a hcp structure magnesium phase and a long-period laminated structure phase at room temperature.

(1) 0.2≤a≤3.0

(2) 0.2≤b≤5.0

(3) 2a-3≤b

In addition, it is preferable that the average particle size of the long-period stacked structure phase is 0.2 μm or more, and there are a plurality of random grain boundaries in the grains of the long-period stacked structure phase, and the grains defined by the random grain boundaries The average particle size of the particles is above 0.05 μm.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the dislocation density of the long-period stacked structure phase is at least one order of magnitude smaller than the dislocation density of the hcp structure magnesium phase.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the volume percentage of the crystal grains of the long-period stacked structure phase is 5% or more.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the plastic processed product has a compound composed of Mg and rare earth elements, a compound of Mg and Zn, a compound of Zn and rare earth elements, and Mg and Zn and rare earth elements. At least one precipitate selected from the precipitate group consisting of compounds of the element-like element.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the total volume percentage of the at least one kind of precipitates exceeds 0% and is 40% or less.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the plastic processing is performed during rolling, extrusion, ECAE, drawing processing, forging, stamping, roll forming, bending, FSW processing, and repeated processing thereof. The processing of at least one of .

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the total amount of deformation during the plastic working is 15 or less.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the total amount of deformation during the plastic working is 10 or less.

Technical scheme 16

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that Y and/or Gd are contained in a total of y atomic % in the above-mentioned Mg, and y satisfies the following formulas (4) and (5).

(4) 0≤y≤4.8

(5) 0.2≤b+y≤5.0

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that at least one element selected from the group consisting of Yb, Tb, Sm, and Nd is contained in the Mg in a total of c atomic %, and c satisfies the following Describe formulas (4) and (5).

(4) 0≤c≤3.0

(5) 0.2≤b+c≤6.0

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that at least one element selected from the group consisting of La, Ce, Pr, Eu, and Mm be contained in total c atomic % in the above-mentioned Mg, c The following expressions (4) and (5) are satisfied.

(4) 0≤c≤3.0

(5) 0.2≤b+c≤6.0

In addition, the so-called Mm (mixed rare earth alloy) is a mixture or alloy of a plurality of rare earth elements mainly composed of Ce and La, and is a residue obtained by refining and removing useful rare earth elements such as Sm and Nd from the ore. Its composition depends on the composition of the ore before refining.

Technical scheme 19

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that at least one element selected from the group consisting of Yb, Tb, Sm, and Nd is contained in total c atomic % in the above-mentioned Mg, and a total of d At least one element selected from the group consisting of La, Ce, Pr, Eu and Mm, c and d satisfy the following formulas (4) to (6).

(4) 0≤c≤3.0

(5) 0≤d≤3.0

(6) 0.2≤b+c+d≤6.0

Technical scheme 20

The high-strength and high-toughness magnesium alloy of the present invention is characterized in that it contains a atomic % of Zn, a total of b atomic % of at least one element selected from the group consisting of Dy, Ho, and Er, and the remainder is composed of Mg. , a and b satisfy the following formulas (1) to (3).

(1) 0.1≤a≤5.0

(2) 0.1≤b≤5.0

(3) 0.5a-0.5≤b

The high-strength and high-toughness magnesium alloy of the present invention is characterized in that it contains a atomic % of Zn, a total of b atomic % of at least one element selected from the group consisting of Dy, Ho, and Er, and the remainder is composed of Mg. , a and b satisfy the following formulas (1) to (3).

(1) 0.1≤a≤3.0

(2) 0.1≤b≤5.0

(3) 2a-3≤b

In addition, the high-strength and high-toughness magnesium alloy is preferably a material subjected to plastic working after cutting a magnesium alloy casting.

The high-strength and high-toughness magnesium alloy of the present invention is characterized in that a magnesium alloy casting containing a atomic % of Zn and a total of b atomic % of Zn selected from the group consisting of Dy, Ho, and Er is produced. At least one element, the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3), the magnesium alloy casting is cut to produce a sheet-shaped casting, and the casting is processed by plastic working. The solidified plastic processed product has a hcp structure magnesium phase and a long-period stacked structure phase at room temperature.

(1) 0.1≤a≤5.0

(2) 0.1≤b≤5.0

(3) 0.5a-0.5≤b

The high-strength and high-toughness magnesium alloy of the present invention is characterized in that a magnesium alloy casting containing a atomic % of Zn and a total of b atomic % of Zn selected from the group consisting of Dy, Ho, and Er is produced. At least one element, the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3), the magnesium alloy casting is cut to produce a sheet-shaped casting, and the casting is processed by plastic working. The solidified plastic processed product has a hcp structure magnesium phase and a long-period stacked structure phase at room temperature.

(1) 0.1≤a≤3.0

(2) 0.1≤b≤5.0

(3) 2a-3≤b

The high-strength and high-toughness magnesium alloy of the present invention is characterized in that a magnesium alloy casting containing a atomic % of Zn and a total of b atomic % of Zn selected from the group consisting of Dy, Ho, and Er is produced. At least one element, the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3), and a sheet-shaped casting is produced by cutting the magnesium alloy casting, and the plastic working is used to make the A plastic processed product in which the casting is solidified, and the plastic processed product obtained by heat-treating the plastic processed product has a hcp structure magnesium phase and a long-period stacked structure phase at room temperature.

(1) 0.1≤a≤5.0

(2) 0.1≤b≤5.0

(3) 0.5a-0.5≤b

The high-strength and high-toughness magnesium alloy of the present invention is characterized in that a magnesium alloy casting containing a atomic % of Zn and a total of b atomic % of Zn selected from the group consisting of Dy, Ho, and Er is produced. At least one element, the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3), and a sheet-shaped casting is produced by cutting the magnesium alloy casting, and the plastic working is used to make the A plastic processed product in which the casting is solidified, and the plastic processed product obtained by heat-treating the plastic processed product has a hcp structure magnesium phase and a long-period stacked structure phase at room temperature.

(1) 0.1≤a≤3.0

(2) 0.1≤b≤5.0

(3) 2a-3≤b

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, preferably, the average particle size of the hcp structure magnesium phase is 0.1 μm or more.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, preferably, the dislocation density of the long-period stacked structure phase is at least one order of magnitude smaller than the dislocation density of the hcp structure magnesium phase.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the volume percentage of the crystal grains of the long-period stacked structure phase is 5% or more.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the plastic processed product has a compound composed of Mg and rare earth elements, a compound of Mg and Zn, a compound of Zn and rare earth elements, and Mg and Zn and rare earth elements. At least one precipitate selected from the precipitate group consisting of compounds of the element-like element.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the total volume percentage of the at least one kind of precipitates exceeds 0% and is 40% or less.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the plastic processing is performed during rolling, extrusion, ECAE, drawing processing, forging, stamping, roll forming, bending, FSW processing, and repeated processing thereof. The processing of at least one of .

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the total amount of deformation during the plastic working is 15 or less. In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the total amount of deformation during the plastic working is 10 or less.

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, the Mg may contain Y and/or Gd in a total of y atomic %, and y satisfies the following formulas (4) and (5).

(4) 0≤y≤4.9

(5) 0.1≤b+y≤5.0

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that at least one element selected from the group consisting of Yb, Tb, Sm, and Nd is contained in the Mg in a total of c atomic %, and c satisfies the following Describe formulas (4) and (5).

(4) 0≤c≤3.0

(5) 0.1≤b+c≤6.0

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that at least one element selected from the group consisting of La, Ce, Pr, Eu, and Mm be contained in total c atomic % in the above-mentioned Mg, c The following expressions (4) and (5) are satisfied.

(4) 0≤c≤3.0

(5) 0.1≤b+c≤6.0

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, it is preferable that at least one element selected from the group consisting of Yb, Tb, Sm, and Nd is contained in total c atomic % in the above-mentioned Mg, and a total of d At least one element selected from the group consisting of La, Ce, Pr, Eu and Mm, c and d satisfy the following formulas (4) to (6).

(4) 0≤c≤3.0

(5) 0≤d≤3.0

(6) 0.1≤b+c+d≤6.0

In addition, in the high-strength and high-toughness magnesium alloy of the present invention, the Mg may contain Al, Th, Ca, Si, Mn, Zr, Ti, Hf, At least one element selected from the group consisting of , Nb, Ag, Sr, Sc, B, C, Sn, Au, Ba, Ge, Bi, Ga, In, Ir, Li, Pd, Sb and V.

The manufacturing method of the high-strength and high-toughness magnesium alloy of the present invention is characterized in that it has:

A step of producing a magnesium alloy casting that contains a atomic % of Zn, a total of b atomic % of at least one element selected from the group consisting of Dy, Ho, and Er, and the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3);

A step of producing a plastically worked product by plastically working the magnesium alloy.

(1) 0.2≤a≤5.0

(2) 0.2≤b≤5.0

(3) 0.5a-0.5≤b

According to the manufacturing method of the high-strength and high-toughness magnesium alloy of the present invention, by performing plastic working on the magnesium alloy casting, the hardness and yield strength of the plastic working product after plastic working can be compared with that of the casting before plastic working. improve.

In addition, in the method for producing a high-strength and high-toughness magnesium alloy of the present invention, between the steps of producing the magnesium alloy cast product and the process of producing the plastic processed product, additionally performing Homogenization heat treatment process. The heat treatment conditions at this time are preferably: the temperature is 400° C. to 550° C., and the treatment time is 1 minute to 1500 minutes.

In addition, in the method for producing a high-strength and high-toughness magnesium alloy of the present invention, a step of heat-treating the plastically worked product may be added after the step of producing the plastically worked product. The heat treatment conditions at this time are preferably: the temperature is 150° C. to 450° C., and the treatment time is 1 minute to 1500 minutes.

The manufacturing method of the high-strength and high-toughness magnesium alloy of the present invention is characterized in that it has:

A step of producing a magnesium alloy casting that contains a atomic % of Zn, a total of b atomic % of at least one element selected from the group consisting of Dy, Ho, and Er, and the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3);

A step of producing a plastically worked product by plastically working the magnesium alloy.

(1) 0.2≤a≤3.0

(2) 0.2≤b≤5.0

(3) 2a-3≤b

In addition, in the method for producing a high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the magnesium alloy casting has a hcp structure magnesium phase and a long-period stacked structure phase.

In addition, in the method for producing a high-strength and high-toughness magnesium alloy according to the present invention, at least one element selected from the group consisting of Yb, Tb, Sm, and Nd may be contained in c atomic % in total in the Mg, c satisfies the following expressions (4) and (5).

(4) 0≤c≤3.0

(5) 0.2≤b+c≤6.0

In addition, in the method for producing a high-strength and high-toughness magnesium alloy according to the present invention, it is preferable that at least c atomic % of at least one selected from the group consisting of La, Ce, Pr, Eu, Mm, and Gd is contained in the Mg. One element, c satisfies the following formulas (4) and (5).

(4) 0≤c≤3.0

(5) 0.2≤b+c≤6.0

In addition, in the method for producing a high-strength and high-toughness magnesium alloy according to the present invention, it is preferable that at least one element selected from the group consisting of Yb, Tb, Sm, and Nd is contained in c atomic % in total in the Mg, At least one element selected from the group consisting of La, Ce, Pr, Eu, Mm, and Gd is contained in d atomic % in total, and c and d satisfy the following formulas (4) to (6).

(4) 0≤c≤3.0

(5) 0≤d≤3.0

(6) 0.2≤b+c+d≤6.0

The manufacturing method of the high-strength and high-toughness magnesium alloy of the present invention is characterized in that it has:

A step of producing a magnesium alloy casting that contains a atomic % of Zn, a total of b atomic % of at least one element selected from the group consisting of Dy, Ho, and Er, and the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3);

A step of producing a sheet-shaped cutting object by cutting the magnesium alloy;

A step of producing a plastic-worked product by solidifying the cut product by plastic working.

(1) 0.1≤a≤5.0

(2) 0.1≤b≤5.0

(3) 0.5a-0.5≤b

The manufacturing method of the high-strength and high-toughness magnesium alloy of the present invention is characterized in that it has:

A step of producing a magnesium alloy casting that contains a atomic % of Zn, a total of b atomic % of at least one element selected from the group consisting of Dy, Ho, and Er, and the remainder is composed of Mg, a and b satisfy the following formulas (1) to (3);

A step of producing a sheet-shaped cutting object by cutting the magnesium alloy;

A step of producing a plastic-worked product by solidifying the cut product by plastic working.

(1) 0.1≤a≤3.0

(2) 0.1≤b≤5.0

(3) 2a-3≤b

In addition, in the method for producing a high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the magnesium alloy casting has a hcp structure magnesium phase and a long-period stacked structure phase.

In addition, in the method for producing a high-strength and high-toughness magnesium alloy according to the present invention, at least one element selected from the group consisting of Yb, Tb, Sm, and Nd may be contained in c atomic % in total in the Mg, c satisfies the following expressions (4) and (5).

(4) 0≤c≤3.0

(5) 0.1≤b+c≤6.0

In addition, in the method for producing a high-strength and high-toughness magnesium alloy according to the present invention, it is preferable that at least c atomic % of at least one selected from the group consisting of La, Ce, Pr, Eu, Mm, and Gd is contained in the Mg. One element, c satisfies the following formulas (4) and (5).

(4) 0≤c≤3.0

(5) 0.1≤b+c≤6.0

In addition, in the method for producing a high-strength and high-toughness magnesium alloy according to the present invention, it is preferable that at least one element selected from the group consisting of Yb, Tb, Sm, and Nd is contained in c atomic % in total in the Mg, At least one element selected from the group consisting of La, Ce, Pr, Eu, Mm, and Gd is contained in d atomic % in total, and c and d satisfy the following formulas (4) to (6).

(4) 0≤c≤3.0

(5) 0≤d≤3.0

(6) 0.1≤b+c+d≤6.0

In addition, in the method for producing a high-strength and high-toughness magnesium alloy of the present invention, the Mg may contain Al, Th, Ca, Si, Mn, Zr, At least one element selected from the group consisting of Ti, Hf, Nb, Ag, Sr, Sc, B, C, Sn, Au, Ba, Ge, Bi, Ga, In, Ir, Li, Pd, Sb, and V .

In addition, in the manufacturing method of the high-strength and high-toughness magnesium alloy of the present invention, the plastic processing may also be rolling, extrusion, ECAE, drawing processing, forging, stamping, roll forming, bending, FSW processing and their The processing of at least one of the processing is repeated. That is, the plastic working may be used alone or in combination among rolling, extrusion, ECAE, stretching, forging, stamping, roll forming, bending, and FSW processing.

In addition, in the method for producing a high-strength and high-toughness magnesium alloy according to the present invention, it is preferable that the total deformation amount during the plastic working is 15 or less, and more preferably, the total deformation amount is 10 or less. In addition, the amount of deformation per one step during the plastic working is preferably not less than 0.002 and not more than 4.6.

In addition, the total amount of deformation refers to the total amount of deformation not eliminated by heat treatment such as annealing. That is, the deformation eliminated by heat treatment in the middle of the manufacturing process is not included in the total deformation amount.

However, in the case of a high-strength and high-toughness magnesium alloy subjected to a step of producing sheet-shaped cuttings, it refers to the total deformation amount when plastic working is performed after producing a material for final solidification molding. That is, the amount of deformation before the final material for curing and forming is not counted in the total amount of deformation. The so-called final material for solidification and molding refers to a sheet material with poor bondability and a tensile strength below 200 MPa. In addition, the solidification molding of a sheet-like material uses processing such as extrusion, rolling, forging, punching, and ECAE. Calendering, extrusion, ECAE, stretching, forging, stamping, roll forming, bending, FSW, etc. can also be used after curing molding. In addition, various plastic processes such as ball milling, repeated forging, and stamping can also be added to the sheet material before the final solidification and forming.

In addition, the method for producing a high-strength and high-toughness magnesium alloy according to the present invention may further include a step of heat-treating the plastically worked product after the step of producing the plastically worked product. In this way, the hardness and yield strength of the plastically processed product after the heat treatment can be further improved compared with those before the heat treatment.

In addition, in the method for producing a high-strength and high-toughness magnesium alloy of the present invention, it is preferable that the conditions of the heat treatment are: more than 200°C and less than 500°C, and more than 10 minutes and less than 24 hours.

In addition, in the manufacturing method of the high-strength and high-toughness magnesium alloy of the present invention, the dislocation density of the hcp structure magnesium phase of the magnesium alloy after the plastic working is preferably greater than the dislocation density of the long-period stacked structure phase by 1 more than an order of magnitude.

As described above, according to the present invention, it is possible to provide a high-strength and high-toughness magnesium alloy having strength and toughness at a practical level and a method for producing the same for expanded applications of magnesium alloys.

Description of drawings

FIG. 1 is a photograph showing the crystal structure of each of the cast materials of Example 1, Comparative Example 1, and Comparative Example 2. FIG.

FIG. 2 is a photograph showing the crystal structure of each of the cast materials of Examples 2 to 4. FIG.

FIG. 3 is a photograph showing the crystal structure of the cast material of Example 5. FIG.

FIG. 4 is a photograph showing the crystal structure of the cast material of Example 6. FIG.

FIG. 5 is a photograph showing crystal structures of cast materials of Examples 7 and 8. FIG.

FIG. 6 is a photograph showing crystal structures of cast materials of Comparative Examples 3 to 9. FIG.

Fig. 7 is a photograph showing a crystal structure of a cast material of a reference example.

Fig. 8 is a diagram showing the composition range of the magnesium alloy according to Embodiment 1 of the present invention.

9 is a diagram showing the composition range of a magnesium alloy according to Embodiment 7 of the present invention.

Detailed ways

Embodiments of the present invention will be described below.

The inventors returned to the basics, started to study the strength and toughness of alloys from 2-element magnesium alloys, and then extended the research to multi-element magnesium alloys. As a result, it was found that a magnesium alloy having a high level of strength and toughness is Mg-Zn-RE (rare earth element) type, and the rare earth element is at least one selected from the group consisting of Y, Dy, Ho, and Er. Magnesium alloys of this element, unlike the prior art, can obtain high strength and high toughness that have not been achieved before at low contents of zinc content of 5.0 atomic % or less and rare earth element content of 5.0 atomic % or less.

A cast alloy having a long-period laminated structure phase can be subjected to plastic working or heat treatment after plastic working to obtain a high-strength, high-ductility, and high-toughness magnesium alloy. In addition, it was discovered that a long-period laminated structure can be formed, and after plastic working or heat treatment for plastic working, an alloy composition with high strength, high ductility, and high toughness can be obtained.

In addition, it has been found that cutting a cast alloy having a long-period laminated structure to produce a sheet-shaped casting, and performing plastic working on the casting, or performing heat treatment after plastic working, is different from the case where the step of cutting into a sheet is not performed. In comparison, magnesium alloys with higher strength, higher ductility, and higher toughness can be obtained. In addition, it was discovered that after forming a long-period laminated structure, cutting into flakes, performing plastic working, or after heat treatment for plastic working, an alloy composition with high strength, high ductility, and high toughness can be obtained.

At least a part of the long-period stacked structure phase can be bent or bent by plastically working the metal having the long-period stacked structure phase. In this way, a metal with high strength, high ductility, and high toughness can be obtained.

In addition, random grain boundaries are included in the bent or bent long-period stacked structure phase. By increasing the strength of this random grain boundary magnesium alloy, grain boundary sliding at high temperature is suppressed, so that high strength can be obtained at high temperature.

In addition, since the hcp structure magnesium phase contains a high density of dislocations, the magnesium alloy is strengthened, and since the dislocation density of the long-period stacked structure phase is low, the ductility and high strength of the magnesium alloy can be improved. change. Preferably, the dislocation density of the long-period laminated structure phase is at least 1 order of magnitude smaller than that of the hcp structure magnesium phase.

(Embodiment 1)

The magnesium alloy according to Embodiment 1 of the present invention is basically a ternary or higher alloy containing Mg, Zn, and a rare earth element, and the rare earth element is one or two selected from the group consisting of Dy, Ho, and Er. elements above.

The composition range of this magnesium alloy is the range enclosed by the line A-B-C-D-E shown in FIG. 8 . That is, when the content of zinc is defined as a atomic %, and the total content of one or more rare earth elements is defined as b atomic %, then a and b satisfy the following formulas (1) to (3 ).

(1) 0.2≤a≤5.0

(2) 0.2≤b≤5.0

(3) 0.5a-0.5≤b

In addition, in the magnesium alloy in which the rare earth element is one or two or more elements selected from the group consisting of Dy, Ho, and Er, Y and/or Gd may be contained in a total of y atomic %. It is preferable to satisfy the following expressions (4) and (5).

(4) 0≤y≤4.8

(5) 0.2≤b+y≤5.0

This is because the toughness (or ductility) tends to decrease especially when the content of zinc is more than 5 atomic %. In addition, when the total content of one or more rare earth elements is 5 atomic % or more, especially the toughness (or ductility) tends to decrease.

In addition, when the content of zinc is less than 0.2 atomic %, or the total content of rare earth elements is less than 0.2 atomic %, at least one of strength and toughness becomes insufficient. Therefore, the lower limit of the content of zinc is set to 0.2 atomic %, and the lower limit of the total content of rare earth elements is set to 0.2 atomic %.

The increase in strength and toughness becomes remarkable when the zinc content is 0.2 to 1.5 atomic %. When the zinc content is around 0.2 atomic %, the strength tends to decrease when the rare earth element content decreases, but even in this range, higher strength and higher toughness than before are exhibited. Therefore, the range of the zinc content of the magnesium alloy of this embodiment is 0.2 atomic % or more and 5.0 atomic % or less at the widest range.

In the Mg-Zn-RE-based magnesium alloy of this embodiment, components other than zinc and rare earth elements having a content within the above-mentioned ranges are magnesium, but impurities may be contained to such an extent that they do not affect the properties of the alloy.

In addition, although the composition range of the magnesium alloy when the rare earth element is one or two or more elements selected from the group consisting of Dy, Ho and Er is set to satisfy the above formulas (1) to (3) However, as a more preferable composition range, it is the range which satisfies following formula (1')-(3').

(1')0.2≤a≤3.0

(2')0.2≤b≤5.0

(3')2a-3≤b

(Embodiment 2)

The magnesium alloy according to Embodiment 2 of the present invention is basically a quaternary or higher alloy containing Mg, Zn, and a rare earth element, and the rare earth element is one or two selected from the group consisting of Dy, Ho, and Er. Among the above elements, the fourth element is one or two or more elements selected from the group consisting of Yb, Tb, Sm, and Nd.

The composition range of this magnesium alloy is: when the content of zinc is set as a atomic %, the total content of one or more rare earth elements is set as b atomic %, and the fourth element of one or two or more When the total content of is c atomic %, a, b, and c satisfy the following formulas (1) to (5).

(1) 0.2≤a≤5.0

(2) 0.2≤b≤5.0

(3) 0.5a-0.5≤b

(4) 0≤c≤3.0

(5) 0.2≤b+c≤6.0

The reason for making the zinc content 5 atomic % or less, the reason for making the total content of one or more rare earth elements 5 atomic % or less, the reason for making the zinc content 0.2 atomic % or more, The reason why the total content of the rare earth elements is 0.2 atomic % or more is the same as that in the first embodiment. In addition, the reason for setting the upper limit of the content of the fourth element to 3.0 atomic % is that the solid solution limit of the fourth element is low. In addition, the reason why the fourth element is contained is that it has the effect of making crystal grains finer and the effect of precipitating intermetallic compounds.

The Mg-Zn-RE magnesium alloy of this embodiment may contain impurities to such an extent that they do not affect the properties of the alloy.

Although the composition range of the magnesium alloy when the rare earth element is one or more elements selected from the group consisting of Dy, Ho and Er is set to satisfy the formulas (1) to (5 ), however, as a more preferable composition range, it is a range satisfying the following formulas (1') to (5').

(1')0.2≤a≤3.0

(2')0.2≤b≤5.0

(3')2a-3≤b

(4')0≤c≤3.0

(5')0.2≤b+c≤6.0

(Embodiment 3)

The magnesium alloy according to Embodiment 3 of the present invention is basically a quaternary or higher alloy containing Mg, Zn, and a rare earth element, and the rare earth element is one or two selected from the group consisting of Dy, Ho, and Er. Among the above elements, the fourth element is one or two or more elements selected from the group consisting of La, Ce, Pr, Eu, Mm, and Gd. In addition, the so-called Mm (mixed rare earth alloy) is a mixture or alloy of a plurality of rare earth elements mainly composed of Ce and La, and is a residue obtained by refining and removing useful rare earth elements such as Sm and Nd from the ore. Its composition depends on the composition of the ore before refining.

The composition range of the magnesium alloy of the present embodiment is: when the content of Zn is represented as a atomic %, the total content of one or more rare earth elements is represented as b atomic %, and one or more rare earth elements are When the total content of the fourth element is c atomic %, a, b, and c satisfy the following expressions (1) to (5).

(1) 0.2≤a≤5.0

(2) 0.2≤b≤5.0

(3) 0.5a-0.5≤b

(4) 0≤c≤3.0

(5) 0.2≤b+c≤6.0

The reason for making the zinc content 5 atomic % or less, the reason for making the total content of one or more rare earth elements 5 atomic % or less, the reason for making the zinc content 0.2 atomic % or more, The reason why the total content of the rare earth elements is 0.2 atomic % or more is the same as that in the first embodiment. In addition, the main reason for setting the upper limit of the content of the fourth element to 3.0 atomic % is that there is almost no solid solution limit of the fourth element. In addition, the reason why the fourth element is contained is that it has the effect of making crystal grains finer and the effect of precipitating intermetallic compounds.

The Mg-Zn-RE magnesium alloy of this embodiment may contain impurities to such an extent that they do not affect the properties of the alloy.

Although the composition range of the magnesium alloy when the rare earth element is one or more elements selected from the group consisting of Dy, Ho and Er is set to satisfy the formulas (1) to (5 ), however, as a more preferable composition range, it is a range satisfying the following formulas (1') to (5').

(1')0.2≤a≤3.0

(2')0.2≤b≤5.0

(3')2a-3≤b

(4')0≤c≤3.0

(5')0.2≤b+c≤6.0

(Embodiment 4)

The magnesium alloy according to Embodiment 4 of the present invention is basically a five-element or higher alloy containing Mg, Zn, and a rare earth element, and the rare earth element is one or two selected from the group consisting of Dy, Ho, and Er. Of the above elements, the fourth element is one or more elements selected from the group consisting of Yb, Tb, Sm, and Nd, and the fifth element is selected from the group consisting of La, Ce, Pr, Eu, Mm, and Gd. 1 or 2 or more elements selected from a group.

The composition range of this magnesium alloy is: when the content of Zn is set to a atomic %, the total content of one or more rare earth elements is set to b atomic %, and the fourth element of one or two or more The total content of the element is c atomic %, and when the total content of one or more than two elements is d atomic %, then a, b, c and d satisfy the following formulas (1) to (6 ).

(1) 0.2≤a≤5.0

(2) 0.2≤b≤5.0

(3) 0.5a-0.5≤b

(4) 0≤c≤3.0

(5) 0≤d≤3.0

(6) 0.2≤b+c+d≤6.0

The reason why the total content of the rare earth element, the fourth element, and the fifth element is 6.0 atomic % or less is that if it exceeds 6 atomic %, it becomes heavy, the raw material cost increases, and the toughness decreases. The reason why the total content of the rare earth element, the fourth element, and the fifth element is 0.2 atomic % or more is that if it is less than 0.2 atomic %, the strength becomes insufficient. In addition, the reason why the fourth element and the fifth element are contained is because there is an effect of making crystal grains finer and an effect of precipitating intermetallic compounds.

The Mg-Zn-RE magnesium alloy of this embodiment may contain impurities to such an extent that they do not affect the properties of the alloy.

Although the composition range of the magnesium alloy when the rare earth element is one or more elements selected from the group consisting of Dy, Ho and Er is set to satisfy the formulas (1) to (6 ), however, as a more preferable composition range, it is a range satisfying the following formulas (1') to (6').

(1')0.2≤a≤3.0

(2')0.2≤b≤5.0

(3')2a-3≤b

(4')0≤c≤3.0

(5')0≤d≤3.0

(6')0.2≤b+c≤6.0

(Embodiment 5)

Examples of the magnesium alloy according to the fifth embodiment of the present invention include magnesium alloys in which Me is added to the compositions of the first to fourth embodiments. Among them, Me is composed of Al, Th, Ca, Si, Mn, Zr, Ti, Hf, Nb, Ag, Sr, Sc, B, C, Sn, Au, Ba, Ge, Bi, Ga, In, Ir, At least one element selected from the group consisting of Li, Pd, Sb, and V. The content of Me is set to be more than 0 atomic % and not more than 2.5 atomic %. When Me is added, other properties can be improved while maintaining high strength and high toughness. For example, it is effective in terms of corrosion resistance and crystal grain refinement.

(Embodiment 6)

A method for producing a magnesium alloy according to Embodiment 6 of the present invention will be described.

A magnesium alloy composed of any one of the compositions of Embodiments 1 to 5 is dissolved and cast to produce a magnesium alloy casting. The cooling rate during casting is 1000K/sec or less, more preferably 100K/sec or less. As the casting process, various processes can be used, for example, high pressure casting, roll casting, inclined plate casting, continuous casting, thixo molding, die casting, etc. can be used. In addition, a process of cutting out a magnesium alloy casting in a predetermined shape may also be used.

Then, a homogenization heat treatment may be performed on the magnesium alloy casting. The heat treatment conditions at this time are preferably set at a temperature of 400° C. to 550° C. and a treatment time of 1 minute to 1500 minutes (or 24 hours).

Then, plastic working is performed on the magnesium alloy casting. As the plastic working method, for example, extrusion, ECAE (equal-channel-angular-extrusion) processing, rolling, drawing and forging, FSW (friction stir welding; friction stir welding) processing, stamping, roll forming, Bending, their repeated processing, etc.

When performing plastic working by extrusion, it is preferable to set the extrusion temperature at 250° C. to 500° C. and to set the area reduction ratio by extrusion at 5% or more.

The ECAE processing method is a method in which the longitudinal direction of the sample is rotated by 90° in each cycle in order to introduce uniform deformation into the sample. Specifically, it is a method of forcibly inserting a magnesium alloy casting as a forming material into the forming hole of a forming mold having an L-shaped forming hole in a cross-sectional shape, especially in the L-shaped forming hole. Stress is applied to the magnesium alloy casting at the portion bent at 90° in the shaped forming hole to obtain a molded body with excellent strength and toughness. The number of cycles of ECAE is preferably 1 to 8 cycles. More preferably 3 to 5 cycles. The temperature during processing of ECAE is preferably 250°C or higher and 500°C or lower.

When performing plastic working by rolling, it is preferable to set the rolling temperature at 250° C. to 500° C. and to set the rolling reduction at 5% or more.

When performing plastic working by stretching, it is preferable to perform stretching at a temperature of 250° C. or higher and 500° C. or lower, and the reduction rate of the cross section of the stretching is 5% or higher.

When performing plastic working by forging, it is preferable to perform the forging at a temperature of not less than 250° C. and not more than 500° C., and the working ratio of the forging is not less than 5%.

For the plastic working of the magnesium alloy casting, it is preferable that the amount of deformation each time is not less than 0.002 and not more than 4.6, and the total amount of deformation is not more than 15. In addition, the plastic working is more preferably with a deformation amount of 0.002 to 4.6 per time, and a total deformation amount of 10 or less.

Moreover, the amount of deformation in ECAE processing is 0.95 to 1.15 per time. For example, when 16 ECAE processing is performed, the total deformation becomes 0.95×16=15.2, and when 8 ECAE processing is performed, the total deformation becomes 0.95×8=7.6.

In addition, the deformation amount of extrusion processing is: when the extrusion ratio is 2.5, it is 0.92/time, when the extrusion ratio is 4, it is 1.39/time, when the extrusion ratio is 10, it is 2.30/time. When the extrusion ratio is 20, it is 2.995/time, when the extrusion ratio is 50, it is 3.91/time, when the extrusion ratio is 100, it is 4.61/time, and when the extrusion ratio is 1000, it is 6.90/time.

As described above, the plastically processed magnesium alloy casting has the hcp structure magnesium phase and the crystal structure of the long-period laminated structure phase at room temperature, and the volume percentage of the crystal grains having the long-period laminated structure phase Above 5% (more preferably above 10%), the average particle size of the hcp structure magnesium phase is above 2 μm, and the average particle size of the long-period laminated structure phase is above 0.2 μm. A plurality of random grain boundaries exist in the crystal grains of the long-period stacked structure phase, and the average grain size of the crystal grains defined by the random grain boundaries is 0.05 μm or more. Although the dislocation density is high in the random grain boundary, the dislocation density is low in the part other than the random grain boundary in the long-period stacked structure phase. Therefore, the dislocation density of the hcp structure magnesium phase is larger than the dislocation density of the long-period stacked structure phase other than the random grain boundary by one order of magnitude or more.

At least a portion of the long-period stacked structural phase is bent or bent. In addition, the plastic processed product may have a precipitate selected from a compound of Mg and rare earth elements, a compound of Mg and Zn, a compound of Zn and rare earth elements, and a compound of Mg and Zn and rare earth elements. of at least one precipitate. The total volume percentage of the precipitates is preferably more than 0% and not more than 40%. In addition, the plastic processed product has hcp-Mg. The Vickers hardness and the yield strength of the plastic-worked product after the above-mentioned plastic working were increased compared with the cast product before plastic working.

Heat treatment may also be performed on a plastic worked product obtained by plastic working the magnesium alloy cast product. The heat treatment conditions are preferably set as follows: the temperature is not less than 200° C. and less than 500° C., and the heat treatment time is 10 minutes to 1500 minutes (or 24 hours). The reason why the heat treatment temperature is set to be lower than 500° C. is because, when it is 500° C. or higher, the amount of deformation due to plastic working is eliminated.

The Vickers hardness and yield strength of the plastic-worked product after the heat treatment were increased compared with the plastic-worked product before the heat treatment. In addition, the plastic processed product after heat treatment also has the crystal structure of the hcp structure magnesium phase and the long-period stacked structure phase at room temperature as before the heat treatment, and the volume percentage of crystal grains having the long-period stacked structure phase is 5% or more (more preferably 10% or more), the average particle size of the hcp structure magnesium phase is above 2 μm, and the average particle size of the long-period stacked structure phase is above 0.2 μm. A plurality of random grain boundaries exist in the crystal grains of the long-period stacked structure phase, and the average grain size of the crystal grains defined by the random grain boundaries is 0.05 μm or more. Although the dislocation density is high in the random grain boundaries, the dislocation density is low in parts other than the random grain boundaries of the long-period stacked structure phase. Therefore, the dislocation density of the hcp structure magnesium phase is larger than the dislocation density of the long-period stacked structure phase other than the random grain boundary by one order of magnitude or more.

At least a portion of the long-period stacked structural phase is bent or bent. In addition, the plastic processed product may have a precipitate selected from a compound of Mg and rare earth elements, a compound of Mg and Zn, a compound of Zn and rare earth elements, and a compound of Mg and Zn and rare earth elements. of at least one precipitate. The total volume percentage of the precipitates is preferably more than 0% and not more than 40%.

According to the above-mentioned Embodiments 1 to 6, for the expanded use of magnesium alloys, for example, as high-tech alloys requiring high performance in both strength and toughness, it is possible to provide magnesium alloys with strength and toughness at a practical level. High-strength and high-toughness magnesium alloy and its manufacturing method.

(Embodiment 7)

The magnesium alloy according to Embodiment 7 of the present invention is an alloy suitable for a plurality of sheet-shaped castings of several mm square or less produced by cutting castings, and is basically a ternary or quaternary containing Mg, Zn, and rare earth elements. In the above alloy, the rare earth element is one or two or more elements selected from the group consisting of Y, Dy, Ho, and Er.

The composition range of this magnesium alloy is the range enclosed by the line A-B-C-D-E shown in FIG. 9 . That is, when the content of zinc is defined as a atomic %, and the total content of one or more rare earth elements is defined as b atomic %, then a and b satisfy the following formulas (1) to (3 ).

(1) 0.1≤a≤5.0

(2) 0.1≤b≤5.0

(3) 0.5a-0.5≤b

In addition, in the magnesium alloy in which the rare earth element is one or two or more elements selected from the group consisting of Dy, Ho, and Er, Y and/or Gd may be contained in a total of y atomic %. It is preferable to satisfy the following expressions (4) and (5).

(4) 0≤y≤4.9

(5) 0.1≤b+y≤5.0

This is because the toughness (or ductility) tends to decrease especially when the content of zinc is more than 5 atomic %. In addition, when the total content of one or more rare earth elements is 5 atomic % or more, especially the toughness (or ductility) tends to decrease.

In addition, when the content of zinc is less than 0.1 atomic %, or the total content of rare earth elements is less than 0.1 atomic %, at least one of strength and toughness becomes insufficient. Therefore, the lower limit of the content of zinc is set to 0.1 atomic %, and the lower limit of the total content of rare earth elements is set to 0.1 atomic %. The reason why the respective lower limits of the zinc content and the total content of rare earth elements can be lowered by 1/2 compared to Embodiment 1 is because it is suitable for sheet castings.

The increase in strength and toughness becomes apparent at 0.5 to 1.5 atomic % of zinc. When the zinc content is around 0.5 atomic %, the strength tends to decrease when the rare earth element content decreases, but even in this range, higher strength and higher toughness than before are exhibited. Therefore, the range of the zinc content of the magnesium alloy of this embodiment is 0.1 atomic % or more and 5.0 atomic % or less at the widest range.

In the Mg-Zn-RE-based magnesium alloy of this embodiment, components other than zinc and rare earth elements having a content within the above-mentioned ranges are magnesium, but impurities may be contained to such an extent that they do not affect the properties of the alloy.

In addition, although the composition range of the magnesium alloy when the rare earth element is one or two or more elements selected from the group consisting of Dy, Ho and Er is set to satisfy the above formulas (1) to (3) However, as a more preferable composition range, it is the range which satisfies following formula (1')-(3').

(1')0.1≤a≤3.0

(2')0.1≤b≤5.0

(3')2a-3≤b

(Embodiment 8)

The magnesium alloy according to Embodiment 8 of the present invention is an alloy suitable for a plurality of sheet-shaped castings of several mm square or less produced by cutting castings, and is basically a quaternary or higher alloy containing Mg, Zn, and rare earth elements. , the rare earth element is one or more elements selected from the group consisting of Dy, Ho, and Er, and the fourth element is one element selected from the group consisting of Yb, Tb, Sm, and Nd or 2 or more elements.

The composition range of the magnesium alloy of the present embodiment is: when the content of zinc is a atomic %, the total content of one or more rare earth elements is b atomic %, and one or more rare earth elements are When the total content of the fourth element is c atomic %, a, b, and c satisfy the following expressions (1) to (5).

(1) 0.1≤a≤5.0

(2) 0.1≤b≤5.0

(3) 0.5a-0.5≤b

(4) 0≤c≤3.0

(5) 0.1≤b+c≤6.0

The Mg-Zn-RE magnesium alloy of this embodiment may contain impurities to such an extent that they do not affect the properties of the alloy.

In addition, although the composition range of the magnesium alloy when the rare earth element is one or two or more elements selected from the group consisting of Dy, Ho and Er is set to satisfy the above formulas (1) to (3) However, as a more preferable composition range, it is the range which satisfies following formula (1')-(3').

(1')0.1≤a≤3.0

(2')0.1≤b≤5.0

(3')2a-3≤b

(Embodiment 9)

The magnesium alloy according to Embodiment 9 of the present invention is an alloy suitable for a plurality of sheet-shaped castings of several mm square or less produced by cutting castings, and is basically a quaternary or quinary containing Mg, Zn, and rare earth elements. In the above alloy, the rare earth element is one or more elements selected from the group consisting of Dy, Ho, and Er, and the fourth element is selected from the group consisting of La, Ce, Pr, Eu, Mm, and Gd. 1 or more elements selected from a group.

The composition range of the magnesium alloy of the present embodiment is: when the content of Zn is represented as a atomic %, the total content of one or more rare earth elements is represented as b atomic %, and one or more rare earth elements are When the total content of the fourth element is c atomic %, a, b, and c satisfy the following expressions (1) to (5).

(1) 0.1≤a≤5.0

(2) 0.1≤b≤5.0

(3) 0.5a-0.5≤b

(4) 0≤c≤3.0

(5) 0.1≤b+c≤6.0

The reason for making the zinc content 5 atomic % or less, the reason for making the total content of one or more rare earth elements 5 atomic % or less, the reason for making the zinc content 0.1 atomic % or more, The reason why the total content of the rare earth elements is 0.1 atomic % or more is the same as that in the seventh embodiment. In addition, the reason for setting the upper limit of the content of the fourth element to 3.0 atomic % is that there is almost no solid solution limit of the fourth element. In addition, the reason why the fourth element is contained is that it has the effect of making crystal grains finer and the effect of precipitating intermetallic compounds.

The Mg-Zn-RE magnesium alloy of this embodiment may contain impurities to such an extent that they do not affect the properties of the alloy.

In addition, although the composition range of the magnesium alloy when the rare earth element is one or two or more elements selected from the group consisting of Dy, Ho and Er is set to satisfy the above formulas (1) to (3) However, as a more preferable composition range, it is the range which satisfies following formula (1')-(3').

(1')0.1≤a≤3.0

(2')0.1≤b≤5.0

(3')2a-3≤b

(Embodiment 10)

The magnesium alloy according to Embodiment 10 of the present invention is an alloy suitable for a plurality of sheet-shaped castings of several mm square or less produced by cutting castings, and is basically a five-element or higher alloy containing Mg, Zn, and rare earth elements. , the rare earth element is one or more elements selected from the group consisting of Dy, Ho, and Er, and the fourth element is selected from the group consisting of Yb, Tb, Sm, Nd, and Gd One or two or more elements, and the fifth element is one or two or more elements selected from the group consisting of La, Ce, Pr, Eu, and Mm.

The composition range of the magnesium alloy of the present embodiment is: when the content of Zn is represented as a atomic %, the total content of one or more rare earth elements is represented as b atomic %, and one or more rare earth elements are When the total content of the fourth element is c atomic %, and the total content of one or more fifth elements is d atomic %, then a, b, c, and d satisfy the following formula (1) ~(4).

(1) 0.1≤a≤5.0

(2) 0.1≤b≤5.0

(3) 0.5a-0.5≤b

(4) 0≤c≤3.0

(5) 0≤d≤3.0

(6) 0.1≤b+c+d≤6.0

Reasons for setting the total content of rare earth elements, fourth elements, and fifth elements to less than 6.0 atomic %, reasons for setting the total content of rare earth elements, fourth elements, and fifth elements to more than 0.1 atomic %, and embodiments 4 is the same.

The Mg-Zn-RE magnesium alloy of this embodiment may contain impurities to such an extent that they do not affect the properties of the alloy.

Although the composition range of the magnesium alloy when the rare earth element is one or two or more elements selected from the group consisting of Dy, Ho and Er is set to satisfy the formulas (1) to (3 ), however, as a more preferable composition range, it is a range satisfying the following formulas (1') to (3').

(1')0.1≤a≤3.0

(2')0.1≤b≤5.0

(3')2a-3≤b

(Embodiment 11)

Examples of the magnesium alloy according to Embodiment 11 of the present invention include magnesium alloys in which Me is added to the composition of Embodiments 7 to 10. Among them, Me is composed of Al, Th, Ca, Si, Mn, Zr, Ti, Hf, Nb, Ag, Sr, Sc, B, C, Sn, Au, Ba, Ge, Bi, Ga, In, Ir, At least one element selected from the group consisting of Li, Pd, Sb, and V. The content of Me is set to be more than 0 atomic % and not more than 2.5 atomic %. When Me is added, other properties can be improved while maintaining high strength and high toughness. For example, it is effective in terms of corrosion resistance and crystal grain refinement.

(Embodiment 12)

A method for producing a magnesium alloy according to Embodiment 12 of the present invention will be described.

A magnesium alloy composed of any one of the compositions of Embodiments 7 to 11 is dissolved and cast to produce a magnesium alloy casting. The cooling rate during casting is 1000K/sec or less, more preferably 100K/sec or less. As this magnesium alloy casting, a material cut out in a given shape from an ingot is used.

Then, a homogenization heat treatment may be performed on the magnesium alloy casting. The heat treatment conditions at this time are preferably set at a temperature of 400° C. to 550° C. and a treatment time of 1 minute to 1500 minutes (or 24 hours).

Then, by cutting this magnesium alloy casting, a plurality of sheet-shaped castings having a square size of several millimeters or less are produced.

Then, the sheet casting may be preformed by compression or plastic working, and subjected to homogenization heat treatment. The heat treatment conditions at this time are preferably set at a temperature of 400° C. to 550° C. and a treatment time of 1 minute to 1500 minutes (or 24 hours). In addition, the preformed molded article may be heat-treated at a temperature of 150°C to 450°C for 1 minute to 1500 minutes (or 24 hours).

Castings in sheet form are generally used, for example, as raw materials for thixo molds.

Furthermore, it is also possible to preform a material mixed with sheet-like castings and ceramic particles by compression or plastic working, and perform homogenization heat treatment. In addition, strong deformation processing may be additionally performed before the sheet-shaped casting is preformed.

Then, the sheet-like casting is solidified and shaped by plastic working the sheet-like casting. As a method of this plastic working, various methods can be used in the same manner as in the sixth embodiment. Furthermore, before the sheet-shaped casting is solidified and formed, repeated processing such as mechanical alloying using a ball mill, a stamper, a high-energy ball mill, or bulk mechanical alloying may be added. In addition, plastic processing or shot blasting can also be added after curing and forming. In addition, the magnesium alloy cast product may be composited with intermetallic compound particles, ceramic particles, fibers, or the like, or the cuttings may be mixed with ceramic particles, fibers, or the like.

The plastic-worked product subjected to plastic working in this way has a crystal structure of a hcp structure magnesium phase and a long-period lamination structure phase at room temperature. At least a portion of the long-period stacked structural phase is bent or bent. The Vickers hardness and the yield strength of the plastic-worked product after the above-mentioned plastic working were increased compared with the cast product before plastic working.

The total amount of deformation during plastic working of the sheet-like casting is preferably 15 or less, and more preferably 10 or less. In addition, the amount of deformation per plastic working is preferably not less than 0.002 and not more than 4.6.

In addition, the total amount of deformation mentioned here means the total amount of deformation not eliminated by heat treatment such as annealing, and is the total amount of deformation when plastic working is performed after the sheet-like casting is preformed. That is, the deformation eliminated by heat treatment in the middle of the manufacturing process is not included in the total deformation amount, and the deformation amount before the sheet-shaped casting is preformed is not included in the total deformation amount.

Heat treatment may also be performed on the plastic-worked product obtained by plastic-working the sheet-shaped cast product. The heat treatment conditions are preferably set as follows: the temperature is not less than 200° C. and less than 500° C., and the heat treatment time is 10 minutes to 1500 minutes (or 24 hours). The reason why the heat treatment temperature is set to be lower than 500° C. is because, when it is 500° C. or higher, the amount of deformation due to plastic working is eliminated.

The Vickers hardness and yield strength of the plastic-worked product after the heat treatment were increased compared with the plastic-worked product before the heat treatment. In addition, the plastic processed product after the heat treatment also has the crystal structure of the hcp structure magnesium phase and the long-period stacked structure phase at room temperature, as before the heat treatment. At least a portion of the long-period stacked structural phase is bent or bent.

In the twelfth embodiment, since the sheet-shaped cast product is produced by cutting the cast product, the structure is refined, so compared with the sixth embodiment, it is possible to produce a plastic-worked product with higher strength, higher ductility, and higher toughness. wait. In addition, the magnesium alloy of the present embodiment can obtain high strength and high toughness characteristics even at a lower concentration of zinc and rare earth elements than the magnesium alloys of embodiments 1 to 6.

According to the above-described seventh to twelfth embodiments, for the expanded use of magnesium alloys, for example, for the use of high-tech alloys requiring high performance in both strength and toughness, it is possible to provide strength and toughness at a practical level. A high-strength, high-toughness magnesium alloy and a manufacturing method thereof.

Example

Examples will be described below.

In Example 1, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % Dy was used.

In Example 2, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % Ho was used.

In Example 3, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % Er was used.

In Example 4, a quaternary system magnesium alloy of 96.5 atomic % Mg-1 atomic % Zn-1 atomic % Y-1.5 atomic % Dy was used.

In Example 5, a quaternary system magnesium alloy of 96.5 atomic % Mg-1 atomic % Zn-1 atomic % Y-1.5 atomic % Er was used.

Each of the magnesium alloys in Examples 4 and 5 is an alloy in which rare earth elements forming a long-period laminated structure are complexly added.

In Example 6, a quaternary system magnesium alloy of 96.5 atomic % Mg-1 atomic % Zn-1.5 atomic % Y-1 atomic % Dy was used.

In Example 7, a quaternary system magnesium alloy of 96.5 atomic % Mg-1 atomic % Zn-1.5 atomic % Y-1 atomic % Er was used.

In Comparative Example 1, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % La was used.

In Comparative Example 2, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % Yb was used.

In Comparative Example 3, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % Ce was used.

In Comparative Example 4, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % Pr was used.

In Comparative Example 5, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % Nd was used.

In Comparative Example 6, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % Sm was used.

In Comparative Example 7, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % Eu was used.

In Comparative Example 8, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % Tm was used.

In Comparative Example 9, a ternary system magnesium alloy of 97 atomic % Mg-1 atomic % Zn-2 atomic % Lu was used.

As a reference example, a binary system magnesium alloy of 98 atomic % Mg-2 atomic % Y was used.

(Structure observation of cast material)

First, ingots having the respective compositions of Examples 1 to 7, Comparative Examples 1 to 9, and Reference Example were produced by high frequency melting in an Ar gas atmosphere, and the shapes of Φ10×60 mm were cut out from these ingots. Structural observation of the cut out cast material was performed by SEM and XRD. Photographs of these crystal structures are shown in FIGS. 1 to 7 .

In FIG. 1 , photographs of crystal structures of Comparative Examples 1 and 2 are shown. In FIG. 2 , photographs of crystal structures of Examples 1 to 3 are shown. In Fig. 3, a photograph of the crystal structure of Example 4 is shown. In Fig. 4, a photograph of the crystal structure of Example 5 is shown. In Fig. 5, photographs of crystal structures of Examples 6 and 7 are shown. In FIG. 6 , photographs of crystal structures of Comparative Examples 3 to 9 are shown. FIG. 7 shows a photograph of the crystal structure of the reference example.

As shown in FIGS. 1 to 5 , in the magnesium alloys of Examples 1 to 7, a crystal structure of a long-period lamination structure is formed. In contrast, as shown in FIG. 1 , FIG. 6 and FIG. 7 , the magnesium alloys of Comparative Examples 1 to 9 and Reference Examples did not form a crystal structure of a long-period laminated structure.

From the crystal structures of each of Examples 1 to 7 and Comparative Examples 1 to 9, the following things were confirmed.

In the Mg-Zn-RE ternary system casting alloy, a long-period stacked structure is formed when RE is Dy, Ho, Er, and when RE is La, Ce, Pr, Nd, Sm, Eu, Gd, Yb When , no long-period stacked structure is formed. The properties of Gd are slightly different from those of La, Ce, Pr, Nd, Sm, Eu, and Yb. Although the addition of Gd alone (must have Zn) will not form a long-period stacked structure, it is different from the long-period stacked structure that forms a long-period stacked structure. When the elements Dy, Ho, and Er are added in combination, a long-period stacked structure can be formed even at 2.5 atomic %.

In addition, when adding Yb, Tb, Sm, Nd, and Gd to Mg-Zn-RE (RE=Dy, Ho, Er), if it is 5.0 atomic % or less, the long-period stacked structure will not be hindered. Formation. In addition, when La, Ce, Pr, Eu, and Mm are added to Mg-Zn-RE (RE=Dy, Ho, Er), if it is 5.0 atomic % or less, the long-period stacked structure will not be hindered. Formation.

The crystal grain size of the casting material of Comparative Example 1 is about 10-30 μm, the crystal grain size of the casting material of Comparative Example 2 is about 30-100 μm, and the crystal grain size of the casting material of Example 1 is 20-60 μm. A large number of crystals were observed. In addition, in the crystal structure of the cast material of Comparative Example 2, fine precipitates existed in the grains.

(Vickers hardness test of cast materials)

Each of the cast materials of Comparative Example 1 and Comparative Example 2 was evaluated by a Vickers hardness test. The Vickers hardness of the cast material of Comparative Example 1 was 75 Hv, and the Vickers hardness of the cast material of Comparative Example 2 was 69 Hv.

(ECAE processing)

ECAE processing was implemented at 400 degreeC about the cast material of each of the said comparative examples 1 and 2. In order to introduce uniform deformation into the sample, the ECAE processing method uses a method of rotating the sample longitudinal direction by 90 degrees in each cycle, and performs 4 and 8 cycles. The processing speed at this time was a constant value of 2 mm/sec.

(Vickers hardness test of ECAE processed materials)

The samples processed by ECAE were evaluated by the Vickers hardness test. The Vickers hardness of the sample after 4 times of ECAE processing was 82 Hv for the sample of Comparative Example 1, and 76 Hv for the sample of Comparative Example 2. Compared with the cast material before ECAE processing, about 10% of the hardness was observed. improve. In the sample subjected to ECAE processing eight times, there was substantially no change in hardness compared to the sample subjected to ECAE processing four times.

(Crystal structure of ECAE processed material)

Structural observation of the sample subjected to ECAE processing was performed by SEM and XRD. In the processed materials of Comparative Examples 1 and 2, the crystallized substances existing on the grain boundaries were fragmented on the order of several μm and dispersed finely and uniformly. In the sample subjected to ECAE processing eight times, there was substantially no change in the structure compared with the sample subjected to ECAE processing four times.

(Tensile test of ECAE processed material)

The samples subjected to ECAE processing were evaluated by a tensile test. Tensile tests were carried out parallel to the extrusion direction at an initial deformation rate of 5 x 10 ^-4 /sec. Regarding the tensile properties of the samples subjected to ECAE processing four times, the samples of Comparative Examples 1 and 2 exhibited a yield stress of 200 MPa or less and an elongation of 2 to 3%.

(Mechanical properties after extrusion of cast alloys of Examples 8 to 44)

A casting material of a magnesium alloy of a ternary system having the composition shown in Tables 1 to 3 was produced, and after heat treatment of the casting material at 500° C. for 10 hours, the casting material was extruded as shown in Tables 1 to 3. The extrusion process was carried out according to the temperature and extrusion ratio. For the extruded materials after extrusion processing, 0.2% proof strength (yield strength), tensile strength, and elongation were measured by a tensile test at the test temperatures shown in Tables 1 to 3. In addition, the hardness (Vickers hardness) of the extruded material was also measured. These measurement results are shown in Tables 1-3.

[Table 1] Example Composition (at.%) Extrusion temperature (℃) Extrusion ratio Experimental temperature (°C) 0.2% Endurance (MPa) Tensile strength (MPa) elongation(%) Hardness (Hv) 8 Mg-1Zn-0.5Dy 350 10 room temperature 338 340 1 78 9 ↓ 350 10 200 212 213 10 10 Mg-1Zn-1Dy 350 10 room temperature 320 321 2.5 85 11 ↓ 350 10 200 270 275 3 12 Mg-1Zn-1.5Dy 350 10 room temperature 344 361 6.5 94 13 ↓ 350 10 200 295 314 6 14 Mg-1Zn-2Dy 350 10 room temperature 350 385 4 96 15 ↓ 350 10 200 301 334 5.5 16 Mg-1Zn-2.5Dy 350 10 room temperature 336 385 7 94 17 ↓ 350 10 200 314 348 6.5 18 Mg-1Zn-3Dy 350 10 room temperature 330 387 9 94 19 ↓ 350 10 200 316 358 6 20 Mg-0.25Zn-2Dy 350 10 room temperature 310 338 4 83 twenty one Mg-0.5Zn-2Dy 350 10 room temperature 334 363 4.5 90 twenty two ↓ 350 10 200 307 337 7.5 twenty three Mg-0.75Zn-2Dy 350 10 room temperature 330 366 4.5 94 twenty four Mg-1Zn-2Dy 350 10 room temperature 350 385 4 96 25 ↓ 350 10 200 301 334 5.5 26 Mg-1.5Zn-2Dy 350 10 room temperature 340 361 8.5 88 27 ↓ 350 10 200 307 329 10 28 Mg-2Zn-2Dy 350 10 room temperature 325 347 10 84 29 ↓ 350 10 200 283 307 13 30 Mg-2.5Zn-2Dy 350 10 room temperature 280 313 10 80 31 ↓ 350 10 200 255 276 12.5

[Table 2] Example Composition (at.%) Extrusion temperature (℃) Extrusion ratio Experimental temperature (°C) 0.2% Endurance (MPa) Tensile strength (MPa) elongation(%) Hardness (Hv) 32 Mg-1Zn-2Er 350 10 room temperature 350 385 4 96 33 ↓ 350 10 200 301 334 5.5 34 Mg-1Zn-0.5Er 350 10 room temperature 320 330 6 78 35 Mg-1Zn-1Er 350 10 room temperature 270 291 12 80 36 Mg-1Zn-15Er 350 10 room temperature 295 321 13.5 88 37 Mg-1Zn-2.5Er 350 10 room temperature 340 375 8 97 38 Mg-1Zn-3Er 350 10 room temperature 300 362 9 98 39 Mg-0.5Zn-2Er 350 10 room temperature 302 327 7 89 40 Mg-1.5Zn-2Er 350 10 room temperature 304 332 10.5 90 41 Mg-2Zn-2Er 350 10 room temperature 284 319 11 84 42 Mg-2.5Zn-2Er 350 10 room temperature 286 311 8 86

[table 3] Example Composition (at.%) Extrusion temperature (℃) Extrusion ratio Experimental temperature (°C) 0.2% Endurance (MPa) Tensile strength (MPa) elongation(%) Hardness (Hv) 43 Mg-1Zn-2Ho 350 10 room temperature 350 385 3 93 44 ↓ 350 10 200 310 340 8

It shows the tensile test and hardness test at room temperature and 200°C after extrusion processing of cast materials with various compositions at various extrusion temperatures with an extrusion ratio of 10 and an extrusion speed of 2.5mm/sec. the result of.

In addition, this invention is not limited to the above-mentioned embodiment and an Example, In the range which does not deviate from the summary of this invention, various changes can be made and implemented.

Claims (57)

1. a high-strength high-toughness magnesium alloy is characterized in that, contains the Zn of a atom %, adds up at least a element of selecting from be made of Dy, Ho and Er a group contain b atom %, and remainder is made of Mg, and a and b satisfy following formula (1)～(3),

(1)0.2≤a≤5.0

(2)0.2≤b≤5.0

(3)0.5a-0.5≤b。

2. a high-strength high-toughness magnesium alloy is characterized in that, contains the Zn of a atom %, adds up at least a element of selecting from be made of Dy, Ho and Er a group contain b atom %, and remainder is made of Mg, and a and b satisfy following formula (1)～(3),

(1)0.2≤a≤3.0

(2)0.2≤b≤5.0

(3)2a-3≤b。

3. high-strength high-toughness magnesium alloy according to claim 1 and 2 is characterized in that, described high-strength high-toughness magnesium alloy is the material that the casting of magnesium alloy divine force that created the universe has been carried out plastic working.

4. high-strength high-toughness magnesium alloy, it is characterized in that, the casting of magnesium alloy divine force that created the universe that is produced as follows, that is, contain the Zn of a atom %, add up at least a element of from constitute by Dy, Ho and Er a group, selecting contain b atom %, remainder is made of Mg, a and b satisfy following formula (1)～(3), have hcp structure magnesium at normal temperatures and reach long period rhythmo structure phase mutually the described casting of magnesium alloy divine force that created the universe having been carried out the plastic working thing after the plastic working

(1)0.2≤a≤5.0

(2)0.2≤b≤5.0

(3)0.5a-0.5≤b。

5. high-strength high-toughness magnesium alloy, it is characterized in that, the casting of magnesium alloy divine force that created the universe that is produced as follows, that is, contain the Zn of a atom %, add up at least a element of from constitute by Dy, Ho and Er a group, selecting contain b atom %, remainder is made of Mg, a and b satisfy following formula (1)～(3), have hcp structure magnesium at normal temperatures and reach long period rhythmo structure phase mutually the described casting of magnesium alloy divine force that created the universe having been carried out the plastic working thing after the plastic working

(1)0.2≤a≤3.0

(2)0.2≤b≤5.0

(3)2a-3≤b。

6. high-strength high-toughness magnesium alloy; It is characterized in that; The casting of magnesium alloy divine force that created the universe that is produced as follows; Namely; The Zn that contains a atom %; Add up at least a element of from consisted of by Dy, Ho and Er a group, selecting contain b atom %; Remainder is made of Mg; A and b satisfy following formula (1)～(3); The described casting of magnesium alloy divine force that created the universe is carried out plastic working and makes the plastic working thing; Have at normal temperatures hcp structure magnesium and reach mutually long period laminated construction phase described plastic working thing having been carried out the plastic working thing after the heat treatment

(1)0.2≤a≤5.0

(2)0.2≤b≤5.0

(3)0.5a-0.5≤b。

7. high-strength high-toughness magnesium alloy; It is characterized in that; The casting of magnesium alloy divine force that created the universe that is produced as follows; Namely; The Zn that contains a atom %; Add up at least a element of from consisted of by Dy, Ho and Er a group, selecting contain b atom %; Remainder is made of Mg; A and b satisfy following formula (1)～(3); The described casting of magnesium alloy divine force that created the universe is carried out plastic working and makes the plastic working thing; Have at normal temperatures hcp structure magnesium and reach mutually long period laminated construction phase described plastic working thing having been carried out the plastic working thing after the heat treatment

(1)0.2≤a≤3.0

(2)0.2≤b≤5.0

(3)2a-3≤b。

8. according to any described high-strength high-toughness magnesium alloy in the claim 4 to 7, it is characterized in that, compare that the dislocation desity of described long period rhythmo structure phase is 1 order of magnitude extremely when young with described hcp structure magnesium dislocation desity mutually.

9. according to any described high-strength high-toughness magnesium alloy in the claim 4 to 8, it is characterized in that the percentage by volume of the crystal grain of described long period rhythmo structure phase is more than 5%.

10. according to any described high-strength high-toughness magnesium alloy in the claim 4 to 9, it is characterized in that described plastic working thing has at least a precipitate of selecting from the precipitate group that the compound by the compound of compound, Zn and the rare earth element of compound, Mg and the Zn of Mg and rare earth element and Mg and Zn and rare earth element constitutes.

11. high-strength high-toughness magnesium alloy according to claim 10 is characterized in that, the total percentage by volume of described at least a precipitate surpasses 0% and below 40%.

12. according to any described high-strength high-toughness magnesium alloy in the claim 4 to 11, it is characterized in that, described plastic working be roll, extrude, at least one the processing in the middle of ECAE, stretch process, forging, punching press, rolling forming, bending, FSW processing and their processing repeatedly.

13., it is characterized in that the total deformation when carrying out described plastic working is below 15 according to any described high-strength high-toughness magnesium alloy in the claim 4 to 12.

14., it is characterized in that the total deformation when carrying out described plastic working is below 10 according to any described high-strength high-toughness magnesium alloy in the claim 4 to 12.

15., it is characterized in that add up to Y and/or the Gd that contains y atom % in described Mg, y satisfies following formula (4) and (5) according to any described high-strength high-toughness magnesium alloy in the claim 1 to 14,

(4)0≤y≤4.8

(5)0.2≤b+y≤5.0。

16. according to any described high-strength high-toughness magnesium alloy in the claim 1 to 15, it is characterized in that, add up at least a element of selecting from be made of Yb, Tb, Sm and Nd a group contain c atom % in described Mg, c satisfies following formula (4) and (5)

(4)0≤c≤3.0

(5)0.2≤b+c≤6.0。

17. according to any described high-strength high-toughness magnesium alloy in the claim 1 to 15, it is characterized in that, add up at least a element of selecting from be made of La, Ce, Pr, Eu and Mm a group contain c atom % in described Mg, c satisfies following formula (4) and (5)

(4)0≤c≤3.0

(5)0.2≤b+c≤6.0。

18. according to any described high-strength high-toughness magnesium alloy in the claim 1 to 15, it is characterized in that, add up at least a element of from constitute by Yb, Tb, Sm and Nd a group, selecting contain c atom % among the described Mg, add up at least a element of from constitute by La, Ce, Pr, Eu and Mm a group, selecting contain d atom %, c and d satisfy following formula (4)～(6)

(4)0≤c≤3.0

(5)0≤d≤3.0

(6)0.2≤b+c+d≤6.0。

19. a high-strength high-toughness magnesium alloy is characterized in that, contains the Zn of a atom %, adds up at least a element of selecting from be made of Dy, Ho and Er a group contain b atom %, remainder is made of Mg, and a and b satisfy following formula (1)～(3),

(1)0.1≤a≤5.0

(2)0.1≤b≤5.0

(3)0.5a-0.5≤b。

20. a high-strength high-toughness magnesium alloy is characterized in that, contains the Zn of a atom %, adds up at least a element of selecting from be made of Dy, Ho and Er a group contain b atom %, remainder is made of Mg, and a and b satisfy following formula (1)～(3),

(1)0.1≤a≤3.0

(2)0.1≤b≤5.0

(3)2a-3≤b。

21., it is characterized in that described high-strength high-toughness magnesium alloy is the material that has carried out plastic working after the casting of magnesium alloy divine force that created the universe is cut according to claim 19 or 20 described high-strength high-toughness magnesium alloys.

22. high-strength high-toughness magnesium alloy; It is characterized in that; The casting of magnesium alloy divine force that created the universe that is produced as follows; Namely; The Zn that contains a atom %; Add up at least a element of from consisted of by Dy, Ho and Er a group, selecting contain b atom %; Remainder is made of Mg; A and b satisfy following formula (1)～(3); Make the mo(u)lding of sheet by cutting the described casting of magnesium alloy divine force that created the universe; Utilize plastic working thing that described mo(u)lding has been solidified in plastic working to have at normal temperatures hcp structure magnesium and reach mutually long period laminated construction phase

(1)0.1≤a≤5.0

(2)0.1≤b≤5.0

(3)0.5a-0.5≤b。

23. high-strength high-toughness magnesium alloy; It is characterized in that; The casting of magnesium alloy divine force that created the universe that is produced as follows; Namely; The Zn that contains a atom %; Add up at least a element of from consisted of by Dy, Ho and Er a group, selecting contain b atom %; Remainder is made of Mg; A and b satisfy following formula (1)～(3); Make the mo(u)lding of sheet by cutting the described casting of magnesium alloy divine force that created the universe; Utilize plastic working thing that described mo(u)lding has been solidified in plastic working to have at normal temperatures hcp structure magnesium and reach mutually long period laminated construction phase

(1)0.1≤a≤3.0

(2)0.1≤b≤5.0

(3)2a-3≤b。

24. high-strength high-toughness magnesium alloy, it is characterized in that, the casting of magnesium alloy divine force that created the universe that is produced as follows, promptly, the Zn that contains a atom %, add up to contain b atom % from by Dy, at least a element of selecting in a group that Ho and Er constitute, remainder is made of Mg, a and b satisfy following formula (1)～(3), make flaky castings by cutting the described casting of magnesium alloy divine force that created the universe, the plastic working thing that making utilizes plastic working that described castings has been solidified has carried out the plastic working thing after the thermal treatment to described plastic working thing and has had hcp structure magnesium at normal temperatures and reach long period rhythmo structure phase mutually

(1)0.1≤a≤5.0

(2)0.1≤b≤5.0

(3)0.5a-0.5≤b。

25. high-strength high-toughness magnesium alloy, it is characterized in that, the casting of magnesium alloy divine force that created the universe that is produced as follows, promptly, the Zn that contains a atom %, add up to contain b atom % from by Dy, at least a element of selecting in a group that Ho and Er constitute, remainder is made of Mg, a and b satisfy following formula (1)～(3), make flaky castings by cutting the described casting of magnesium alloy divine force that created the universe, the plastic working thing that making utilizes plastic working that described castings has been solidified has carried out the plastic working thing after the thermal treatment to described plastic working thing and has had hcp structure magnesium at normal temperatures and reach long period rhythmo structure phase mutually

(1)0.1≤a≤3.0

(2)0.1≤b≤5.0

(3)2a-3≤b。

26., it is characterized in that the median size of described hcp structure magnesium phase is more than 0.1 μ m according to any described high-strength high-toughness magnesium alloy in the claim 22 to 25.

27., it is characterized in that according to any described high-strength high-toughness magnesium alloy in the claim 22 to 26, to compare with described hcp structure magnesium dislocation desity mutually, the dislocation desity of described long period rhythmo structure phase is an order of magnitude extremely when young.

28., it is characterized in that the percentage by volume of the crystal grain of described long period rhythmo structure phase is more than 5% according to any described high-strength high-toughness magnesium alloy in the claim 22 to 27.

29. according to any described high-strength high-toughness magnesium alloy in the claim 22 to 28, it is characterized in that described plastic working thing has at least a precipitate of selecting from the precipitate group that the compound by the compound of compound, Zn and the rare earth element of compound, Mg and the Zn of Mg and rare earth element and Mg and Zn and rare earth element constitutes.

30. high-strength high-toughness magnesium alloy according to claim 29 is characterized in that, the total percentage by volume of described at least a precipitate surpasses 0% and below 40%.

31. according to any described high-strength high-toughness magnesium alloy in the claim 22 to 30, it is characterized in that, described plastic working be roll, extrude, at least one the processing in the middle of ECAE, stretch process, forging, punching press, rolling forming, bending, FSW processing and their processing repeatedly.

32., it is characterized in that the total deformation when carrying out described plastic working is below 15 according to any described high-strength high-toughness magnesium alloy in the claim 22 to 31.

33., it is characterized in that the total deformation when carrying out described plastic working is below 10 according to any described high-strength high-toughness magnesium alloy in the claim 22 to 31.

34., it is characterized in that add up to Y and/or the Gd that contains y atom % in described Mg, y satisfies following formula (4) and (5) according to any described high-strength high-toughness magnesium alloy in the claim 19 to 33,

(4)0≤y≤4.9

(5)0.1≤b+y≤5.0。

35. according to any described high-strength high-toughness magnesium alloy in the claim 19 to 34, it is characterized in that, add up at least a element of selecting from be made of Yb, Tb, Sm and Nd a group contain c atom % in described Mg, c satisfies following formula (4) and (5)

(4)0≤c≤3.0

(5)0.1≤b+c≤6.0。

36. according to any described high-strength high-toughness magnesium alloy in the claim 19 to 34, it is characterized in that, add up at least a element of selecting from be made of La, Ce, Pr, Eu and Mm a group contain c atom % in described Mg, c satisfies following formula (4) and (5)

(4)0≤c≤3.0

(5)0.1≤b+c≤6.0。

37. according to any described high-strength high-toughness magnesium alloy in the claim 19 to 34, it is characterized in that, in described Mg, add up at least a element of from constitute by Yb, Tb, Sm and Nd a group, selecting contain c atom %, add up at least a element of from constitute by La, Ce, Pr, Eu and Mm a group, selecting contain d atom %, c and d satisfy following formula (4)～(6)

(4)0≤c≤3.0

(5)0≤d≤3.0

(6)0.1≤b+c+d≤6.0。

38. according to any described high-strength high-toughness magnesium alloy in the claim 1 to 37, it is characterized in that, in described Mg, add up to contain to surpass 0 atom % and at least a element of from constitute by Al, Th, Ca, Si, Mn, Zr, Ti, Hf, Nb, Ag, Sr, Sc, B, C, Sn, Au, Ba, Ge, Bi, Ga, In, Ir, Li, Pd, Sb and V a group, selecting below 2.5 atom %.

39. the manufacture method of a high-strength high-toughness magnesium alloy is characterized in that, possesses:

The operation of the casting of magnesium alloy divine force that created the universe that is produced as follows promptly, contains the Zn of a atom %, adds up at least a element of selecting from be made of Dy, Ho and Er a group contain b atom %, and remainder is made of Mg, and a and b satisfy following formula (1)～(3);

By described magnesium alloy is carried out the operation that the plastic working thing is made in plastic working,

(1)0.2≤a≤5.0

(2)0.2≤b≤5.0

(3)0.5a-0.5≤b。

40. the manufacture method of a high-strength high-toughness magnesium alloy is characterized in that, possesses:

The operation of the casting of magnesium alloy divine force that created the universe that is produced as follows promptly, contains the Zn of a atom %, adds up at least a element of selecting from be made of Dy, Ho and Er a group contain b atom %, and remainder is made of Mg, and a and b satisfy following formula (1)～(3);

By described magnesium alloy is carried out the operation that the plastic working thing is made in plastic working,

(1)0.2≤a≤3.0

(2)0.2≤b≤5.0

(3)2a-3≤b。

41. the manufacture method according to claim 39 or 40 described high-strength high-toughness magnesium alloys is characterized in that, the described casting of magnesium alloy divine force that created the universe has hcp structure magnesium and reaches long period rhythmo structure phase mutually.

42. manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 30 to 41, it is characterized in that, add up at least a element of selecting from be made of Yb, Tb, Sm and Nd a group contain c atom % in described Mg, c satisfies following formula (4) and (5)

(4)0≤c≤3.0

(5)0.2≤b+c≤6.0。

43. manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 40 to 42, it is characterized in that, in described Mg, add up at least a element of from constitute by La, Ce, Pr, Eu, Mm and Gd a group, selecting contain c atom %, c satisfies following formula (4) and (5)

(4)0≤c≤3.0

(5)0.2≤b+c≤6.0。

44. manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 39 to 41, it is characterized in that, in described Mg, add up at least a element of from constitute by Yb, Tb, Sm and Nd a group, selecting contain c atom %, add up at least a element of from constitute by La, Ce, Pr, Eu, Mm and Gd a group, selecting contain d atom %, c and d satisfy following formula (4)～(6)

(4)0≤c≤3.0

(5)0≤d≤3.0

(6)0.2≤b+c+d≤6.0。

45. the manufacture method of a high-strength high-toughness magnesium alloy is characterized in that, possesses:

The operation of the casting of magnesium alloy divine force that created the universe that is produced as follows promptly, contains the Zn of a atom %, adds up at least a element of selecting from be made of Dy, Ho and Er a group contain b atom %, and remainder is made of Mg, and a and b satisfy following formula (1)～(3);

Make the operation of flaky cutting object by cutting described magnesium alloy;

By utilizing the curing of plastic working to make the operation of plastic working thing to described cutting object,

(1)0.1≤a≤5.0

(2)0.1≤b≤5.0

(3)0.5a-0.5≤b。

46. the manufacture method of a high-strength high-toughness magnesium alloy is characterized in that, possesses:

The operation of the casting of magnesium alloy divine force that created the universe that is produced as follows promptly, contains the Zn of a atom %, adds up at least a element of selecting from be made of Dy, Ho and Er a group contain b atom %, and remainder is made of Mg, and a and b satisfy following formula (1)～(3);

Make the operation of flaky cutting object by cutting described magnesium alloy;

By utilizing the curing of plastic working to make the operation of plastic working thing to described cutting object,

(1)0.1≤a≤3.0

(2)0.1≤b≤5.0

(3)2a-3≤b。

47. the manufacture method according to claim 46 or 47 described high-strength high-toughness magnesium alloys is characterized in that, the described casting of magnesium alloy divine force that created the universe has hcp structure magnesium and reaches long period rhythmo structure phase mutually.

48. manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 45 to 47, it is characterized in that, add up at least a element of selecting from be made of Yb, Tb, Sm and Nd a group contain c atom % in described Mg, c satisfies following formula (4) and (5)

(4)0≤c≤3.0

(5)0.1≤b+c≤6.0。

49. manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 45 to 47, it is characterized in that, in described Mg, add up at least a element of from constitute by La, Ce, Pr, Eu, Mm and Gd a group, selecting contain c atom %, c satisfies following formula (4) and (5)

(4)0≤c≤3.0

(5)0.1≤b+c≤6.0。

50. manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 45 to 47, it is characterized in that, in described Mg, add up at least a element of from constitute by Yb, Tb, Sm and Nd a group, selecting contain c atom %, add up at least a element of from constitute by La, Ce, Pr, Eu, Mm and Gd a group, selecting contain d atom %, c and d satisfy following formula (4)～(6)

(4)0≤c≤3.0

(5)0≤d≤3.0

(6)01≤b+c+d≤6.0。

51. manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 39 to 50, it is characterized in that, in described Mg, add up to contain to surpass 0 atom % and at least a element of from constitute by Al, Th, Ca, Si, Mn, Zr, Ti, Hf, Nb, Ag, Sr, Sc, B, C, Sn, Au, Ba, Ge, Bi, Ga, In, Ir, Li, Pd, Sb and V a group, selecting below 2.5 atom %.

52. manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 39 to 51, it is characterized in that, described plastic working be roll, extrude, at least one the processing in the middle of ECAE, stretch process, forging, punching press, rolling forming, bending, FSW processing and their processing repeatedly.

53. manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 39 to 52, it is characterized in that, described high-strength high-toughness magnesium alloy, be when carrying out described plastic working total deformation at the high-strength high-toughness magnesium alloy below 15.

54. manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 39 to 52, it is characterized in that, described high-strength high-toughness magnesium alloy is that total deformation when carrying out described plastic working is at the high-strength high-toughness magnesium alloy below 10.

55. the manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 39 to 54 is characterized in that, after the operation of making described plastic working thing, also possesses the operation that described plastic working thing is heat-treated.

56. the manufacture method according to the described high-strength high-toughness magnesium alloy of claim 55 is characterized in that, described heat treated condition is: more than 200 ℃ and less than 500 ℃, more than 10 minutes and less than 24 hours.

57. manufacture method according to any described high-strength high-toughness magnesium alloy in the claim 39 to 56, it is characterized in that the dislocation desity of hcp structure magnesium phase of having carried out the magnesium alloy after the described plastic working is bigger 1 more than the order of magnitude than the dislocation desity of long period rhythmo structure phase.

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