CN101407878B - A kind of ductility magnesium alloy and preparation method thereof - Google Patents

Abstract

The invention provides a tough magnesium alloy with good room temperature plasticity and a preparation method of the tough magnesium alloy. The mass percent content of the ductile magnesium alloy is: 0.5-5% Mn, 0.5-5% Sn, 0.05-5% Pb, and the rest is Mg. The preparation method is as follows: according to the mass percentage of 0.5-5% Mn, 0.5-5% Sn, 0.05-5% Pb, and the rest is Mg, the proportion of alloy components is mixed, and the above-mentioned prepared pure Mg ingot, pure Sn strips, pure Pb blocks, and Mn blocks are heated and melted together in a N ₂ /SF ₆ mixed protective atmosphere. When the temperature rises to 705-735°C, they are kept for 4-8 minutes and then cooled to obtain a magnesium alloy; the mixed protective atmosphere contains N ₂ and SF ₆ in a volume ratio of 10:90.

Description

A kind of ductility magnesium alloy and preparation method thereof

1. Technical field

The invention relates to a ductile magnesium alloy and a preparation method thereof, in particular to a ductile magnesium alloy containing manganese, lead and tin and a preparation method thereof, belonging to the technical field of magnesium alloys.

2. Background technology

Magnesium alloys are widely used in the manufacture of industrial products because of their high specific strength and specific stiffness. However, the plasticity and toughness of the existing common magnesium alloys are relatively poor. At present, there are only some studies on high-plasticity magnesium alloys: 200610026842.X proposes a self-generated quasi-crystal-reinforced high-plastic deformation magnesium alloy, which belongs to the technical field of metal materials. The inventive components and their weight percentages are: 2-10% Zn, 0.5-6% Gd, 0-1.0% Zr, impurity elements Fe<0.005%, Ni<0.002%, and the rest is Mg. The alloy of the invention contains quasicrystalline phases, which are formed in-situ in the form of dendrites in the as-cast structure. After extrusion or rolling hot deformation process, the quasicrystalline phases are broken and distributed along the deformation direction. At the same time, during the extrusion or rolling process In this process, the dispersed secondary quasi-crystalline phases are precipitated inside the matrix and at the grain boundaries, thereby enhancing the properties of the alloy.

200810069464.2 provides a wrought magnesium alloy with high yield ratio and high plasticity. The weight percentage of each component of the alloy is zinc 1.0%-2.0%, zirconium 0.1%-0.6%, rare earth erbium 0.1%-0.8%, and the rest For magnesium and unavoidable impurities. Erbium combines with impurity elements in the alloy, magnesium, and oxygen involved in the alloy liquid to form fine dispersed precipitates, which can effectively purify the alloy, promote dynamic recrystallization during thermal deformation, and hinder the growth of recrystallized grains.

200710170765.X provides a gadolinium-containing die-casting heat-resistant high-zinc-magnesium alloy and its preparation method. The alloy composition and its weight percentage are: zinc: 6-10%, aluminum: 3-7%, gadolinium: 0.2-2.0%, impurities Element Fe<0.005%, Cu<0.015%, Ni<0.002%, and the rest is magnesium. Preheat pure magnesium, pure zinc, pure aluminum and Mg-25%Gd, then put pure magnesium into a furnace with gas protection for melting, and immediately add pure zinc and pure aluminum, pure zinc and Skim off the surface scum after the pure aluminum is completely melted, continue to heat up, add Mg-25%Gd master alloy, skim off the surface scum after it is completely melted, then stir, adjust the furnace temperature, refine, stir, then stand still, and finally put the alloy Lower the liquid temperature and skim off the surface scum for die casting. This technology improves the mechanical properties of the alloy at room temperature and high temperature, and the creep properties of the alloy.

The above patent applications are all based on the magnesium-zinc master alloy, adding a certain amount of rare earth elements and other elements to improve the toughness and plasticity of the magnesium alloy. The degree of improvement is limited by the parent alloy, and no independent toughness magnesium alloy system has been formed. .

3. Contents of the invention

Solve the problem:

Aiming at the above-mentioned technical defects, the present invention provides a tough magnesium alloy with good room temperature plasticity.

In addition, the present invention also provides a preparation method of the above tough magnesium alloy.

The object of the present invention is achieved by the following measures:

A ductile magnesium alloy, the mass percent of the alloy composition is: 0.5-5% Mn, 0.5-5% Sn, 0.05-5% Pb, and the rest is Mg.

Wherein, the alloy also contains 0.5-4% Sr element by mass percentage;

Wherein, the alloy also contains Zr element with a mass percentage of 0.01-3%;

Wherein, the alloy also contains 0.001-1% of rare earth elements by mass.

A preparation method of a tough magnesium alloy, the preparation steps are: according to the mass percentage of 0.5-5% Mn, 0.5-5% Sn, 0.05-5% Pb, and the rest is Mg, the proportion of the alloy components is mixed, and the above-mentioned Prepared pure Mg ingots, pure Sn strips, pure Pb blocks, and Mn blocks are heated and melted together in a N ₂ /SF ₆ mixed protective atmosphere. When the temperature rises to 705-725°C, they are kept for 4-8 minutes and then cooled to obtain magnesium. alloy; wherein the volume ratio of N ₂ and SF ₆ in the mixed protective atmosphere is 10:90.

Wherein, 0.5-4% Sr metal is added in the preparation process.

Wherein, Zr metal with a mass percent content of 0.01-3% is also added during the preparation process.

Wherein, 0.001-1% of rare earth elements such as La, Pr, Ce, Nd, and Sm elements are added in the preparation process.

Beneficial effects of the present invention:

The ductile magnesium alloy of the present invention only uses conventional elements such as common tin and lead, avoiding the use of a large amount of rare and precious elements, and the cost of the alloy is relatively low.

Under the action of a certain amount of Mn, Sr and Zr, the effect of tin and lead on increasing the toughness of magnesium is more obvious. The addition of rare earth elements can also improve the toughness and plasticity of magnesium alloys. Mn and Sr have a strong solid solution strengthening effect, and Zr has a grain refining effect. Rare earth elements have the effect of dispersion strengthening and fine grain strengthening. If it is less than the content range, the solid solution strengthening or dispersion strengthening or fine grain strengthening effect of the elements will not be exerted; if it exceeds the above range, too many compounds with larger sizes will appear, which will reduce the toughness of the alloy.

In the preparation process of the present invention, pure Mg ingots, pure Sn strips, pure Pb blocks, Sr intermediate alloys, etc. are loaded into the furnace at one time, and N ₂ /SF ₆ mixed protective atmosphere is used, so the production cost is low and the alloy preparation process is simple.

4. Description of drawings

Figure 1 is a metallographic structure diagram of an alloy containing Sn3%, Pb2%, Mn2%, Sr2%, Zr2%, and the rest is Mg.

In the structure, the black is the grain boundary, the gray is the grain, and the white spot is the dispersed compound.

5. Specific implementation

The present invention will be further described below in conjunction with examples, the value range of the mass percentage content in the following examples indicates that the quality of the raw material can be taken arbitrarily within the content range, and each embodiment can form a variety of dosage relationships.

Embodiment one,

The preparation method of the ductile magnesium alloy, the preparation steps are: according to the mass percentage content of 0.5-5% Mn, 0.5-5% Sn, 0.05-5% Pb, and the rest is Mg, the proportion of the alloy composition is carried out, and the above-mentioned The pure Mg ingots, pure Sn strips, pure Pb blocks, and Mn blocks are heated and melted together in a N2/SF6 mixed protective atmosphere. When the temperature rises to 705-725 ° C, they are kept for 4-8 minutes and then cooled to obtain a magnesium alloy; The volume ratio of _N2 and _SF6 in the protective atmosphere is 10:90.

Embodiment two,

The preparation method of the ductile magnesium alloy, the preparation steps are: according to the mass percentage content of 0.5-5% Mn, 0.5-5% Sn, 0.05-5% Pb, 0.5-4% Sr, and the rest is Mg. For ingredients, heat and melt the above-mentioned pure Mg ingot, pure Sn bar, pure Pb block, Mn block, and Mg-Sr intermediate alloy block together in a N ₂ /SF ₆ mixed protective atmosphere. When the temperature rises to 705-725°C , keep warm for 4-8 minutes and then cool to obtain a magnesium alloy; wherein: the volume ratio of N ₂ and SF ₆ in the mixed protective atmosphere is 10:90; the mass percentage of Sr in the Mg-Sr intermediate alloy block is 40%.

Embodiment three,

The preparation method of the ductile magnesium alloy, the preparation steps are: according to the mass percentage content of 0.5-5% Mn, 0.5-5% Sn, 0.05-5% Pb, 0.01-3% Zr, and the rest is Mg. For ingredients, heat and melt the above-mentioned pure Mg ingot, pure Sn bar, pure Pb block, Mn block, and Mg-Zr intermediate alloy block together in a N ₂ /SF ₆ mixed protective atmosphere. When the temperature rises to 705-725°C , keep warm for 4-8 minutes and then cool to obtain a magnesium alloy; wherein: the volume ratio of N ₂ and SF ₆ in the mixed protective atmosphere is 10:90; the mass percentage of Zr in the Mg-Zr intermediate alloy block is 30%.

Embodiment four,

The preparation method of the ductile magnesium alloy, the preparation steps are as follows: according to the mass percentage content is 0.5-5% Mn, 0.5-5% Sn, 0.05-5% Pb, 0.5-4% Sr, 0.01-3% Zr, Pr is 0.03 %, Ce is 0.03%, La is 0.02%, and the rest is Mg, the alloy components are proportioned for batching, and the above-mentioned pure Mg ingot, pure Sn bar, pure Pb block, Mn block, Mg-Sr intermediate alloy block, The Mg-Zr intermediate alloy block is heated and melted together in the N ₂ /SF ₆ mixed protective atmosphere. When the temperature rises to 705-725°C, the above-mentioned rare earth elements are added into the magnesium alloy liquid in the form of pure material fine particles with a bell jar, finely The average particle diameter is not more than 1mm. After 4-8 minutes of heat preservation, the magnesium alloy is obtained by cooling; the volume ratio of N ₂ and SF ₆ in the mixed protective atmosphere is 10:90; the mass percentage of Sr in the Mg-Sr intermediate alloy block is 40%; the Mg-Zr intermediate The mass percentage of Zr in the alloy block is 30%.

Performance comparison experiment:

The following table shows the toughness detection index parameters of magnesium alloys with different compositions, wherein the comparison alloy is a product of the prior art, and product 1-product 5 are products obtained by adopting the technology of the present invention.

Alloy No. Composition (mass percentage) Impact toughness/J/cm² Comparative Alloy Al??? is 9%, Zn is 1%, and the rest is Mg 8 Comparative Alloy Sn is 2%, Pb is 3%, and the rest is Mg 12 Product 1 Sn is 3%, Pb is 2%, Mn is 3%, and the rest is Mg 28 Product 2 Sn is 3%, Pb is 2%, Mn is 2%, Sr is 2%, and the rest is Mg 27 Product 3 Sn is 3%, Pb is 2%, Mn is 2%, Zr is 2%, and the rest is Mg 29 Product 4 Sn is 3%, Pb is 2%, Mn is 2%, Sr is 2%, Zr is 2%, and the rest is Mg (alloy metallographic structure as shown in Figure 1) 33 Product 5 Sn is 3%, Pb is 2%, Mn is 3%, Zr is 1%, Pr is 0.001%, Ce is 0.03%, La is 0.005%, Nd is 0.005%, Sm is 0.001%, and the rest is Mg 35

Claims (2)

1. A tough magnesium alloy, the mass percentage of alloy composition is: 0.5～5%Mn, 0.5～5%Sn, 0.05～5%Pb, 0.5～4%Sr, 0.01～3%Zr, 0.001～1 % rare earth elements, the rest is Mg. 2. A method for preparing a ductile magnesium alloy, the preparation steps being: 0.5-5% Mn, 0.5-5% Sn, 0.05-5% Pb, 0.5-4% Sr, 0.01-3% Zr according to the mass percentage , 0.001~1% rare earth elements, and the rest are Mg alloy components for proportioning, and the prepared pure Mg ingot, pure Sn bar, pure Pb block, Mn block, Mg-Sr master alloy block, Mg-Zr master alloy Block, heated and melted together in N ₂ /SF ₆ mixed protective atmosphere, when the temperature rises to 705~735°C, add the above rare earth elements into the magnesium alloy liquid in the form of pure material fine particles with a bell jar, the rare earth element fine particles average The diameter does not exceed 1mm, and the magnesium alloy is obtained by cooling after 4-8 minutes of heat preservation; the volume ratio of _N2 and _SF6 in the mixed protective atmosphere is 10:90; the mass percentage of Sr in the Mg-Sr master alloy block is 40% ; The mass percentage of Zr in the Mg-Zr master alloy block is 30%.

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