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WO2010032893A1 - Magnesium alloy and manufacturing method thereof - Google Patents

Magnesium alloy and manufacturing method thereof Download PDF

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Publication number
WO2010032893A1
WO2010032893A1 PCT/KR2008/005655 KR2008005655W WO2010032893A1 WO 2010032893 A1 WO2010032893 A1 WO 2010032893A1 KR 2008005655 W KR2008005655 W KR 2008005655W WO 2010032893 A1 WO2010032893 A1 WO 2010032893A1
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WIPO (PCT)
Prior art keywords
magnesium
magnesium alloy
alloy
additive
compound
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
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PCT/KR2008/005655
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French (fr)
Inventor
Shae Kwang Kim
Jin Kyu Lee
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Korea Institute of Industrial Technology KITECH
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Korea Institute of Industrial Technology KITECH
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Publication of WO2010032893A1 publication Critical patent/WO2010032893A1/en
Anticipated expiration legal-status Critical
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C23/00—Alloys based on magnesium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D21/00—Casting non-ferrous metals or metallic compounds so far as their metallurgical properties are of importance for the casting procedure; Selection of compositions therefor
    • B22D21/002—Castings of light metals
    • B22D21/007—Castings of light metals with low melting point, e.g. Al 659 degrees C, Mg 650 degrees C
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D21/00—Casting non-ferrous metals or metallic compounds so far as their metallurgical properties are of importance for the casting procedure; Selection of compositions therefor
    • B22D21/02—Casting exceedingly oxidisable non-ferrous metals, e.g. in inert atmosphere
    • B22D21/04—Casting aluminium or magnesium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/02—Making non-ferrous alloys by melting
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/10—Alloys containing non-metals
    • C22C1/1036—Alloys containing non-metals starting from a melt
    • C22C1/1047—Alloys containing non-metals starting from a melt by mixing and casting liquid metal matrix composites
    • C22C1/1052—Alloys containing non-metals starting from a melt by mixing and casting liquid metal matrix composites by mixing and casting metal matrix composites with reaction
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C23/00—Alloys based on magnesium
    • C22C23/02—Alloys based on magnesium with aluminium as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C2202/00—Physical properties

Definitions

  • the present invention relates to a magnesium alloy and a method for producing the same.
  • magnesium is the lightest metal in practical use at present.
  • Magnesium and its alloys (hereafter collectively referred to as 'magnesium alloys') are of growing interest as lightweight structural materials due to their high specific strength and specific 'stiffness.
  • magnesium alloys are expected to be useful as replacements for resinous materials.
  • Magnesium alloys are currently produced by various processes, such as die casting and thixocasting, and are widely used as casing materials for electronic devices and electric home appliances where high strength is not critical.
  • Other practical applications of magnesium alloys are automobile parts, for example, handles and cylinder head covers, for the purpose of weight reduction.
  • Magnesium alloy solutions i.e. molten magnesium alloys prepared by heating are liable to ignite.
  • protective gases are used to prevent molten magnesium alloys from being ignited.
  • Representative protective gases include SF 6 , SO 2 , CO 2 , HFC-134a, NovecTM612, inert gases, and mixtures thereof.
  • SF 6 most of the protective gases are harmful to humans and cause metallic equipment to corrode.
  • many protective gases are categorized as greenhouse gases, and thus regulations regarding their use are becoming more stringent.
  • SF 6 has a global warming potential 23,900 times that of CO 2 .
  • regulatory guidelines restrict the use of SF 6 and much research is actively underway to replace SF 6 .
  • the present invention has been made in an effort to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a magnesium alloy produced using a protective gas in a reduced amount or without the use of any protective gas, and a method for producing the magnesium alloy.
  • a further object of the present invention is to provide a magnesium alloy produced using an additive capable of improving the cleanness of molten magnesium in a melting furnace or during transfer or feeding, and a method for producing the magnesium alloy.
  • Another object of the present invention is to provide a magnesium alloy that does not encounter the problems of poor flowability, hot cracking, mold sticking, etc. during production to achieve improved casting, forming, welding and powder metallurgy (PM) performance characteristics, and a method for producing the magnesium alloy.
  • Another object of the present invention is to provide a magnesium alloy produced using a cheap additive and a protective gas in a reduced amount or without the use of any protective gas, thus lowering the production cost, and a method for producing the magnesium aljoy.
  • Another object of the present invention is to provide a magnesium alloy that uses an additive causing no change in original alloy specification to execute the inherent application of the alloy, and a method for producing the magnesium alloy.
  • Another object of the present invention is to provide a magnesium alloy whose mechanical properties are improved by grain refinement and internal soundness, and a method for producing the magnesium alloy.
  • Another object of the present invention is to provide a magnesium alloy with improved welding and joint performance characteristics, and a method for producing the magnesium alloy.
  • Another object of the present invention is to provide a magnesium alloy with improved resistance to oxidation and ignition that can be safely used in a variety of applications, and a method for producing the magnesium alloy.
  • Still another object of the present invention is to provide a magnesium alloy with improved recyclability depending on the type of a flux and temperature control during recycling, and a method for producing the magnesium alloy.
  • the above and other objects can be accomplished by the provision of a magnesium alloy comprising magnesium grains and an additive compound present at grain boundaries defined by the magnesium grains but absent in the magnesium grains.
  • the additive compound may be selected from: a compound of magnesium and an alkali metal; a compound of magnesium and an alkaline earth metal; a compound of a constituent material of the magnesium alloy other than magnesium and an alkali metal; and a compound of a constituent material of the magnesium alloy other than magnesium and an alkaline earth metal.
  • the magnesium grains may be pure magnesium grains or magnesium alloy grains.
  • the additive compound may be present in an amount of 0.0001 to 30 parts by weight, based on 100 parts by weight of the magnesium alloy. In an embodiment, the additive compound may have a size of 0.1 to 500 ⁇ m.
  • the magnesium alloy may have an ignition temperature of 500 to 1 ,500 0 C.
  • the magnesium alloy may be selected from the group consisting of a casting alloy, a wrought alloy, a creep alloy, a damping alloy, a biodegradable alloy, a powder metallurgy alloy, and mixtures thereof.
  • a method for producing a magnesium alloy comprising melting magnesium in a crucible at 600 to 800 0 C under a protective gas atmosphere to form molten magnesium, adding an additive to the molten magnesium, stirring the molten mixture for 1 to 400 minutes, casting the molten mixture in a mold at 100 to 300 0 C, and cooling the cast product.
  • the magnesium may be pure magnesium or a magnesium alloy.
  • the additive may be selected from an alkali metal, an alkali metal oxide, an alkali metal compound, an alkaline earth metal, an alkaline earth metal oxide, an alkaline earth metal compound, and mixtures thereof.
  • the alkali metal oxide may be selected from sodium oxide, potassium oxide, and a mixture thereof.
  • the alkaline earth metal oxide may be selected from beryllium oxide, magnesium oxide, calcium oxide, strontium oxide, and mixtures thereof.
  • the alkaline earth metal compound may be selected from calcium carbide (CaC 2 ), calcium cyanamide (CaCN 2 ), calcium carbonate (CaCOs), calcium sulfate hemihydrate (CaSO 4 ), and mixtures thereof.
  • the additive may be added in an amount of 0.0001 to 30 parts by weight, based on 100 parts by weight of the magnesium alloy.
  • the additive may have a size of 0.1 to 500 ⁇ m. In an embodiment, the additive may be added to increase the ignition temperature and hardness of the magnesium alloy and to reduce the required amount of the protective gas.
  • the present invention has the following advantageous effects.
  • the use of the additive increases the ignition temperature of the magnesium alloy and inhibits the oxidation of the magnesium alloy, so that the protective gas categorized as a greenhouse gas can be used in a reduced amount or the need for the use of the protective gas can be eliminated.
  • the use of the additive can improve the cleanness of the molten magnesium in a melting furnace or during transfer or feeding.
  • the use of the cheap additive and the use of the protective gas in a reduced amount or no use of the protective gas can contribute to a reduction in the production cost of the magnesium alloy.
  • the additive causes no change in the original alloy specification of the magnesium alloy so that the inherent application of the magnesium alloy can be executed.
  • the use of the additive leads to grain refinement and internal soundness of the magnesium alloy, resulting in an improvement in the mechanical properties of the magnesium alloy.
  • the use of the additive inhibits the oxidation of the magnesium alloy and increases the ignition temperature of the magnesium alloy, so that the magnesium alloy can be safely used in a variety of applications.
  • the additive in the form of a compound present in the grain boundaries but absent in the magnesium grains does not respond to a flux supplied and temperature changes during recycling of the magnesium alloy, thus ensuring good recyclability of the magnesium alloy. That is, recycling of the magnesium alloy requires no additional processing for the addition of the additive.
  • FIG. 1 is a flow chart illustrating a method for producing a magnesium alloy according to the present invention
  • FIG. 2 is an image showing the structure of a magnesium alloy produced by a method of the present invention
  • FIGS. 3 through 8 are images showing the results of electron probe micro analysis (EPMA) for a magnesium alloy produced by a method of the present invention
  • FIGS. 9 through 12 are images showing the results of transmission electron microscopy (TEM) for a magnesium alloy produced by a method of the present invention.
  • FIGS. 13 and 14 are graphs showing the results of protective gas reduction experiments of magnesium alloys produced by a method of the present invention.
  • FIG. 15 is a graph showing the results of thermogravimetric analysis (TGA) for a magnesium alloy produced by a method of the present invention.
  • FIGS. 16 and 17 are graphs showing the results of Auger emission spectroscopy (AES) for an AZ91 D magnesium alloy and a magnesium alloy produced by a method of the present invention
  • FIG. 18 is a graph showing the hardness values of magnesium alloys produced by a method of the present invention at room temperature and high temperatures;
  • FIG. 19 is a graph showing the ignition temperatures of magnesium alloys produced by a method of the present invention under an ambient atmosphere and under a nitrogen atmosphere;
  • FIG. 20 is a graph showing the hardness of magnesium alloys produced by a method of the present invention at room temperature
  • FIG. 21 is a graph showing the ignition temperatures of magnesium alloys produced by a method of the present invention under an ambient atmosphere and under a nitrogen atmosphere;
  • FIG. 22 shows surface images of billets of magnesium alloys produced by a method of the present invention
  • FIG. 23 is a graph showing the ignition temperatures of magnesium alloys produced by a method of the present invention.
  • FIG. 24 is a graph showing the hardness of magnesium alloys produced by a method of the present invention.
  • FIG. 25 shows images of the structures of an AZ91 D magnesium alloy and a magnesium alloy produced by a method of the present invention
  • FIG. 26 is a table showing the hardness data of magnesium alloys produced by a method of the present invention.
  • FIG. 27 is a graph showing the ignition temperature of a magnesium alloy produced by a method of the present invention
  • FIG. 28 shows images of the structures of an AZ91 D magnesium alloy and a magnesium alloy produced by a method of the present invention
  • FIG. 29 is a table showing the hardness data of magnesium alloys produced by a method of the present invention.
  • FIG. 30 is a graph showing the ignition temperature of a magnesium alloy produced by a method of the present invention.
  • FIG. 31 is a graph showing the ignition temperatures of magnesium alloys produced by a method of the present invention.
  • FIG. 32 is a graph showing the hardness of magnesium alloys produced by a method of the present invention.
  • FIGS. 33 and 34 are graphs showing the results of ignition experiments of magnesium alloys produced by a method of the present invention
  • FIGS. 35 and 36 are graphs showing the results of protective gas reduction experiments of magnesium alloys produced by a method of the present invention
  • FIGS. 37 and 38 are graphs showing the results of ignition experiments of magnesium alloys produced by a method of the present invention.
  • FIGS. 39 and 40 are surface images of magnesium alloys produced in the absence (FIG. 39) and presence (FIG. 40) of a protective gas
  • FIG. 41 is a surface image of a magnesium alloy produced by a method of the present invention.
  • FIG. 1 is a flow chart illustrating a method for producing a magnesium alloy according to the present invention.
  • the method of the present invention comprises the following steps: formation of molten magnesium (S1), addition of an additive (S2), stirring (S3), casting (S4) and cooling (S5).
  • step S1 magnesium is put into a crucible and heated to 600 to
  • the protective gas serves to inhibit the ignition of the magnesium.
  • the protective gas is selected from SF 6 , SO 2 , CO 2 , HFC-134a, NovecTM612, inert gases, and equivalents thereof. These protective gases may be used alone or as a mixture of two or more thereof.
  • the magnesium may be selected from pure magnesium, magnesium alloys, and equivalents thereof.
  • magnesium alloys include, but are not limited to, AZ91 D, AM20, AM30, AM50, AM60, AZ31 , AS41 , AS31 , AS21X, AE42, AE44, AX51 , AX52, AJ50X, AJ52X, AJ62X, MRM 53, MRI230, AM-HP2, Mg-Al, Mg-Al-Re, Mg-Al-Sn, Mg-Zn- Sn, Mg-Si, Mg-Zn-Y, and equivalents thereof.
  • step S2 the additive added to the molten magnesium is in the form of a powder.
  • an alkali metal there can be used an alkali metal, an alkali metal oxide, an alkali metal compound, an alkaline earth metal, an alkaline earth metal oxide, an alkaline earth metal compound, or an equivalent thereof.
  • a mixture of these additives may also be used.
  • the alkali metal oxide may be selected from sodium oxide, potassium oxide and equivalents thereof. These alkali metal oxides may be used alone or as a mixture of two or more thereof.
  • the alkaline earth metal oxide may be selected from beryllium oxide, magnesium oxide, calcium oxide, strontium oxide, and mixtures thereof.
  • the alkaline earth metal compound may be selected from calcium carbide (CaC 2 ), calcium cyanamide (CaCN 2 ), calcium carbonate (CaCO 3 ), calcium sulfate hemihydrate (CaSO 4 ), and mixtures thereof.
  • any material may be used as the additive so long as it can increase the ignition temperature of the magnesium alloy, reduce the oxidation of the magnesium alloy or decrease the required amount of the protective gas.
  • the additive may be added in an amount of 0.0001 to 30 parts by weight, based on 100 parts by weight of the magnesium alloy. If the amount of the additive added is less than 0.0001 parts by weight, the intended effects (i.e. increased ignition temperature, reduced oxidation and decreased amount of the protective gas) of the additive are negligible. Meanwhile, if the amount of the additive added is more than 30 parts by weight, the inherent characteristics of the magnesium or magnesium alloy are not exhibited.
  • the additive may have a size of 1 to 500 ⁇ m. It is practically difficult and economically undesirable to prepare the additive in a size smaller than 1 ⁇ m. Meanwhile, the additive larger than 500 ⁇ m may not react with the molten magnesium.
  • step S3 the molten mixture is stirred for 1 to 400 minutes.
  • a stirring time of less than 1 minute does not ensure sufficient mixing of the additive with the molten magnesium, while a stirring time of more than 400 is unnecessary because further improvement of stirring effects is not attained.
  • the additive is present in the form of an intermetallic compound outside the magnesium or magnesium alloy grains, i.e. at grain boundaries defined by the magnesium grains or magnesium alloy grains, rather than inside the magnesium or magnesium alloy grains. That is, the additive is in the form of an additive compound. Specifically, the additive is in the form of: a compound of magnesium and an alkali metal; a compound of magnesium and an alkaline earth metal; a compound of a constituent material of the magnesium alloy other than magnesium and an alkali metal; or a compound of a constituent material of the magnesium alloy other than magnesium and an alkaline earth metal.
  • the other constituent elements (e.g., oxygen, carbon, nitrogen, etc.) of the additive float on the surface of the molten magnesium and are removed by manual or automatic means.
  • the molten mixture is cast in a mold at 100 to 300 0 C.
  • the mold may be selected from metal molds, ceramic molds, graphite molds and equivalents thereof.
  • the casting may be performed by gravity casting, continuous casting and equivalent processes thereof. However, there is no restriction on the materials of the mold and the casting processes.
  • step S5 the cast product is cooled to room temperature, and then the final magnesium alloy (e.g., magnesium alloy ingot) is taken out of the mold.
  • the magnesium alloy produced by the method of the present invention is composed of magnesium grains and an additive compound present at grain boundaries defined by the magnesium grains but absent in the magnesium grains, as will be explained later.
  • the additive added during production of the magnesium alloy is distinguished from the additive compound present in the final magnesium alloy.
  • the additive compound present in the magnesium alloy is in the form of an intermetallic compound.
  • FIG. 2 is an image showing the structure of a magnesium alloy 1 produced by the method of the present invention. As shown in FIG. 2, the magnesium alloy 1 comprises magnesium grains 2 and an additive compound 3.
  • the additive compound 3 is present at grain boundaries defined by the magnesium grains 2 but is absent in the magnesium grains 2.
  • the additive compound 3 is in the form of an intermetallic compound.
  • the magnesium grains 2 may be selected from pure magnesium grains, magnesium alloy grains, and equivalents thereof.
  • the additive compound 3 may be selected from: a compound of magnesium and an alkali metal; a compound of magnesium and an alkaline earth metal; a compound of a constituent material of the magnesium alloy other than magnesium and an alkali metal; and a compound of a constituent material of the magnesium alloy other than magnesium and an alkaline earth metal.
  • the additive compound 3 may be present in an amount of 0.0001 to 30 parts by weight, based on 100 parts by weight of the magnesium alloy.
  • the additive compound may have a size of 0.1 to 500 ⁇ m. The critical meanings of the numerical limitations in the content and size of the additive compound 3 have been already explained above.
  • the magnesium alloy 1 of the present invention may have a hardness (HRF) of 40 to 80. However, the hardness of the magnesium alloy 1 may vary depending on various conditions such as processing and annealing.
  • the magnesium alloy 1 has an ignition temperature of 500 to
  • the magnesium alloy may be selected from the group consisting of a casting alloy, a wrought alloy, a creep alloy, a damping alloy, a biodegradable alloy, a powder metallurgy alloy, and mixtures thereof.
  • the casting alloy may be produced from a mixture of AZ91 D, AM20, AM50 or AM60 and CaX (e.g., CaO, CaC 2 or CaCN 2 ).
  • the wrought alloy may be produced from a mixture of AZ31 or AM30 and CaX.
  • the creep alloy may be produced from a mixture of Mg-Al or Mg-Al- Re and CaX or SrO or a mixture of Mg-Al-Sn or Mg-Zn-Sn and ,CaX.
  • the damping alloy may be produced from a mixture of pure Mg, Mg-Si or SiCp/Mg and CaO.
  • the biodegradable alloy may be produced from a mixture of pure
  • the powder metallurgy alloy may be produced from a mixture of Mg-Zn-(Y) and CaX.
  • the yield of the calcium oxide having a size smaller than 100 ⁇ m was 45%. That is, 0.45 parts by weight of the calcium oxide was melted in the corresponding molten magnesium.
  • the yields of the calcium oxide having a size of 100-200 ⁇ m and the calcium oxide having a size of 200-500 ⁇ m were drastically lowered to 0.78% and 0.42%, respectively.
  • FIGS. 3 through 8 are images showing the results of electron probe micro analysis (EPMA) for the magnesium alloy produced by the method of the present invention.
  • EPMA electron probe micro analysis
  • FIG. 3 is a back scattering electron image of the magnesium alloy.
  • the magnesium alloy was substantially composed of grains and grain boundaries defined by the grains.
  • FIG. 4 is an image for magnesium, which is indicated by the red areas, and clearly shows that the magnesium was composed of a number of grains and grain boundaries defined by the grains. In FIG. 4, the blue areas indicate the absence of magnesium.
  • FIG. 5 shows the presence of a small amount of aluminum (red areas) in the grain boundaries.
  • FIG. 6 shows the presence of zinc (red areas) in a much smaller amount than aluminum.
  • FIG. 7 shows the presence of a small amount of calcium (red areas) in the grain boundaries.
  • FIG. 8 shows the substantial absence of oxygen.
  • FIGS. 9 through 12 are images showing the results of transmission electron microscopy (TEM) for a magnesium alloy produced by the method of the present invention.
  • FIG. 9 is a magnified TEM image.
  • the central black area indicates AI 2 Ca as an aluminum-calcium compound.
  • FIG. 10 is an image of magnesium present in areas other than the area of the aluminum-calcium compound.
  • FIGS. 11 and 12 are images of aluminum and calcium, respectively. These results demonstrate that aluminum and calcium were present in the form of an intermetallic compound in the magnesium grain boundaries.
  • FIGS. 13 and 14 are graphs showing the results of protective gas reduction experiments of magnesium alloys produced by the method of the present invention.
  • the graphs of FIGS. 13 and 14 were obtained from experiments at 68O 0 C as a molten metal temperature for die casting and 72O 0 C indicating an overheated state, respectively.
  • “sealed” refers to a state in which ambient air was not introduced
  • “unsealed” refers to a state in which ambient air was introduced.
  • 1,000 ppm SF 6 was necessary to inhibit ignition in the production of AZ91D, AZ91D-0.04wt%CaO and AZ91 D- 0.13wt%CaO in the unsealed state at 68O 0 C.
  • 500 ppm SF 6 was necessary to inhibit ignition in the production of AZ91 D and AZ91 D- 0.04wt%CaO
  • about 300 ppm SF 6 was necessary to inhibit ignition in the production of AZ91 D-0.13wt%CaO in the sealed state. Consequently, the amount of the protective gas necessary to inhibit ignition was decreased with increasing content of the additive at the operation temperature for die casting in the sealed state.
  • FIG. 15 is a graph showing the results of thermogravimetric analysis (TGA) for a magnesium alloy produced by the method of the present invention.
  • the x axis shows time and the y axis shows an increment in weight (%).
  • the weight of AZ91 D sharply increased with the passage of time, indicating rapid oxidation of the magnesium alloy.
  • the weight of AZ91 D-0.14wt%CaO gradually increased with the passage of time, indicating slow oxidation of the magnesium alloy.
  • the weight of AZ91 D and AZ91 D-0.14wt%CaO increased to 113% and 101 %, respectively.
  • FIGS. 16 and 17 are graphs showing the results of Auger emission spectroscopy (AES) for an AZ91 D magnesium alloy and a magnesium alloy produced by the method of the present invention.
  • AES Auger emission spectroscopy
  • the x axis shows sputtering time and the y axis shows the atomic contents ration of oxygen detected.
  • About 40 atomic contents ration of oxygen was detected in AZ91 D until about 9 minutes after sputtering, and thereafter, the amount of oxygen detected decreased, indicating that a relatively thick oxide film was formed in AZ91 D.
  • FIG. 16 is graphs showing the results of Auger emission spectroscopy (AES) for an AZ91 D magnesium alloy and a magnesium alloy produced by the method of the present invention.
  • the x axis shows sputtering time
  • the y axis shows the atomic contents ration of oxygen detected.
  • About 40 atomic contents ration of oxygen was detected in AZ91 D until about 9 minutes after sputtering,
  • FIG. 18 is a graph showing the hardness values' of AZ91 D magnesium alloys produced by the method of the present invention at room temperature and high temperatures.
  • FIG. 18 is a graph showing the ignition temperature of magnesium alloys produced by the method of the present invention.
  • the ignition temperature of the magnesium alloys increased with increasing content of calcium oxide.
  • the ignition temperature of the AZ91 D magnesium alloy under an ambient atmosphere was about 49O 0 C and that of the AZ91 D magnesium alloy was about 51O 0 C under a nitrogen atmosphere, whereas the ignition temperatures of the magnesium alloys containing calcium oxide were increased by at least 100 0 C in proportion to the content of the additive.
  • FIG. 20 is a graph showing the hardness of AZ91 D magnesium alloys produced by the method of the present invention at room temperature.
  • the hardness values of the AZ91 D magnesium alloys containing different strontium oxide amounts (0.02-0.48 wt%) were increased with increasing strontium oxide content.
  • the AZ91 D magnesium alloy containing no strontium oxide had a hardness of about 57
  • the AZ91 D magnesium alloy containing a small amount of strontium oxide had a hardness of about 65 at room temperature.
  • FIG. 21 is a graph showing the ignition temperatures of AZ91 D magnesium alloys produced by the method of the present invention under an ambient atmosphere and under a nitrogen atmosphere.
  • the ignition temperatures of the AZ91 D magnesium alloy containing no strontium oxide were about 49O 0 C and 51O 0 C under an ambient atmosphere and under a nitrogen atmosphere, respectively, while the ignition temperatures of the AZ91 D magnesium alloys containing different amounts of strontium oxide were increased by at least 100 0 C. (Example 3)
  • FIG. 22 shows surface images of billets of AZ91 D magnesium alloys for die casting produced by the method of the present invention.
  • the surface of the billet of the AZ91D magnesium alloy containing 0.0001 wt% of beryllium oxide was clean without being oxidized or ignited despite the presence of a very small amount of the alkaline earth metal oxide.
  • the surface of the billet of the AZ91 D magnesium alloy containing 0.5 wt% of magnesium oxide was clean without being oxidized or ignited despite the presence of a small amount of the alkaline earth metal oxide.
  • FIG. 23 is a graph showing the ignition temperatures of AZ91 D magnesium alloys for die casting produced by the method of the present invention.
  • the ignition temperatures of the AZ91 D magnesium alloy containing 0.0001 wt% of beryllium oxide and the AZ91D magnesium alloy containing 0.5 wt% of magnesium oxide were increased due to the presence of the alkaline earth metal oxides, leading to an improvement in mechanical properties and oxidation resistance.
  • FIG. 24 is a graph showing the hardness of AZ91 D magnesium alloys for die casting produced by the method of the present invention.
  • the hardness values of the AZ91 D magnesium alloy containing 0.0001 wt% of beryllium oxide and the AZ91 D magnesium alloy containing 0.5 wt% of magnesium oxide were increased due to the presence of the alkaline earth metal oxides.
  • FIG. 25 shows images of the structures of an AZ91 D magnesium alloy containing no additive and an AZ91D magnesium alloy produced by the method of the present invention.
  • FIG. 26 is a table showing the hardness data of AZ91 D magnesium alloys produced by the method of the present invention. As shown in FIG. 26, the AZ91 D magnesium alloys containing calcium cyanamide as a calcium compound were measured to have an average hardness of about 66, which is about 4 higher than the hardness (about 62) of an AZ91 D magnesium alloy containing no additive.
  • FIG. 27 is a graph showing the ignition temperature of an AZ91 D magnesium alloy containing no additive and an AZ91 D magnesium alloy produced by the method of the present invention.
  • the ignition temperature of the AZ91 D magnesium alloy containing calcium cyanamide as a calcium compound reached about 54O 0 C under a nitrogen atmosphere, which is about 3O 0 C higher than the ignition temperature (51O 0 C) of the AZ91 D magnesium alloy containing no additive.
  • FIG. 28 shows images of the structures of an AZ91 D magnesium alloy containing no additive and an AZ91 D magnesium alloy produced by the method of the present invention.
  • FIG. 29 is a table showing the hardness data of AZ91 D magnesium alloys produced by the method of the present invention.
  • the AZ91 D magnesium alloys containing calcium carbide as a calcium compound were measured to have an average hardness of about 65.3, which is about 3 higher than the hardness (about 62) of an AZ91 D magnesium alloy containing no additive.
  • FIG. 30 is a graph showing the ignition temperatures of an AZ91 D magnesium alloy containing no additive and an AZ91 D magnesium alloy produced by the method of the present invention.
  • the ignition temperature of the AZ91 D magnesium alloy containing calcium carbide as a calcium compound reached about 54O 0 C under a nitrogen atmosphere, which is about 3O 0 C higher than the ignition temperature (51O 0 C) of the AZ91 D magnesium alloy containing no additive.
  • FIG. 31 is a graph showing the ignition temperatures of magnesium alloys produced by the method of the present invention.
  • the ignition temperatures of the magnesium alloy AZ91 D-0.007wt%CaCN 2 containing calcium cyanamide (CaCN 2 ) and the magnesium alloy AZ91 D-0.03wt%CaC 2 containing calcium cyanamide (CaCN 2 ) were much higher than the ignition temperature of a pure magnesium alloy AZ91 D, indicating that the magnesium alloys produced by the method of the present invention had better heat resistance. These results lead to the conclusion that the ignition temperatures of the magnesium alloys were dramatically increased due to the presence of the calcium compound.
  • FIG. 32 is a graph showing the hardness of AM50 magnesium alloys produced by the method of the present invention.
  • the AM50 magnesium alloy containing no calcium oxide, the AM50 magnesium alloy containing about 0.05% by weight of calcium oxide and the AM50 magnesium alloy containing about 0.15% by weight of calcium oxide were found to have hardness values of about 50, indicating that little influence was given to the microstructure and hardness of the magnesium alloys due to the addition of a small amount of calcium oxide.
  • FIGS. 33 and 34 are graphs showing the results of ignition experiments of AM50 magnesium alloys produced by the method of the present invention.
  • the AM50 magnesium alloy containing no calcium oxide had an ignition temperature of about 57O 0 C
  • the AM50 magnesium alloy containing 0.05% by weight of calcium oxide had an ignition temperature of about 590 0 C
  • the AM50 magnesium alloy containing 0.15% by weight of calcium oxide had an ignition temperature of about 61O 0 C under an ambient atmosphere.
  • the AM50 magnesium alloy containing no calcium oxide had an ignition temperature of about 55O 0 C
  • the AM50 magnesium alloy containing 0.05% by weight of calcium oxide had an ignition temperature of about 57O 0 C
  • the AM50 magnesium alloy containing 0.15% by weight of calcium oxide had an ignition temperature of about 64O 0 C under a nitrogen atmosphere. From these results, it can be seen that the presence of the additive increased the ignition temperature of the magnesium alloys.
  • FIGS. 35 and 36 are graphs showing the results of protective gas reduction experiments of magnesium alloys produced by the method of the present invention.
  • the graphs of FIGS. 35 and 36 were obtained from experiments at 68O 0 C as a molten metal temperature for die casting and 72O 0 C indicating an overheated state, respectively.
  • FIGS. 37 and 38 are graphs showing the results of ignition experiments of AZ31 magnesium alloy containing no calcium oxide and AZ31 magnesium alloys produced by the method of the present invention.
  • the AZ31 magnesium alloy containing no calcium oxide had an ignition temperature of about 57O 0 C under an ambient atmosphere, while the AZ31 magnesium alloy containing 0.3% by weight of calcium oxide had an ignition temperature of about 61O 0 C under an ambient atmosphere. That is, the presence of the additive increased the ignition temperature of the AZ31 magnesium alloy.
  • the AZ31 magnesium alloy containing no calcium oxide had an ignition temperature of about 64O 0 C under a nitrogen atmosphere, while the AZ31 magnesium alloy containing 0.3% by weight of calcium oxide had an ignition temperature of about 69O 0 C under a nitrogen atmosphere. That is, the presence of the additive increased the ignition temperature of the AZ31 magnesium alloy.
  • FIGS. 39 and 40 are surface images of AZ31 magnesium alloys produced in the absence of (FIG. 39) and presence (FIG. 40) of a protective gas
  • FIG. 41 is a surface image of a cast sheet of a magnesium alloy produced by the method of the present invention.
  • the AZ31 magnesium alloy produced without the use of any protective gas was ignited and its surface turned black.
  • a metal oxide was incorporated into the AZ31 magnesium alloy produced by spraying a protective gas, leaving cracks on the surface of the magnesium alloy.

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Abstract

A magnesium alloy with improved resistance to oxidation and ignition is provided. The magnesium alloy comprises magnesium grains and an additive compound present at grain boundaries defined by the magnesium grains but absent in the magnesium grains. Further provided is a method for producing the magnesium alloy. The method comprises melting magnesium in a crucible at 600 to 800°C under a protective gas atmosphere to form molten magnesium, adding an additive to the molten magnesium, stirring the molten mixture for 1 to 400 minutes, casting the molten mixture in a mold at 100 to 300°C, and cooling the cast product. According to the method, the amount of the protective gas used can be reduced.

Description

MAGNESIUM ALLOYAND MANUFACTURING METHOD THEREOF
[Technical Field] The present invention relates to a magnesium alloy and a method for producing the same.
[Background Art]
In general, magnesium is the lightest metal in practical use at present. Magnesium and its alloys (hereafter collectively referred to as 'magnesium alloys') are of growing interest as lightweight structural materials due to their high specific strength and specific 'stiffness. In addition, magnesium alloys are expected to be useful as replacements for resinous materials. Magnesium alloys are currently produced by various processes, such as die casting and thixocasting, and are widely used as casing materials for electronic devices and electric home appliances where high strength is not critical. Other practical applications of magnesium alloys are automobile parts, for example, handles and cylinder head covers, for the purpose of weight reduction. Magnesium alloy solutions (i.e. molten magnesium alloys) prepared by heating are liable to ignite. Various kinds of protective gases are used to prevent molten magnesium alloys from being ignited. Representative protective gases include SF6, SO2, CO2, HFC-134a, Novec™612, inert gases, and mixtures thereof. However, most of the protective gases are harmful to humans and cause metallic equipment to corrode. Particularly, many protective gases are categorized as greenhouse gases, and thus regulations regarding their use are becoming more stringent. For example, SF6 has a global warming potential 23,900 times that of CO2. In advanced countries, regulatory guidelines restrict the use of SF6 and much research is actively underway to replace SF6.
On the other hand, the addition of calcium (Ca) to magnesium alloys is known to effectively inhibit ignition and oxidation of the magnesium alloys at high temperatures, but it causes the disadvantages of poor flowability, hot cracking, mold sticking, etc. The market price of calcium per kg amounts to about 200 dollars, which is responsible for the high production cost of magnesium alloys. Further, calcium varies the original alloy specification of magnesium alloys to reduce the availability of the magnesium alloys. Moreover, calcium is completely removed during recycling of magnesium alloys, thus considerably deteriorating the recyclability of the magnesium alloys. That is, the recycling of magnesium alloys needs continuous addition of calcium, which becomes a cause of increased production cost of the magnesium alloys.
[Disclosure] [Technical Problem]
The present invention has been made in an effort to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a magnesium alloy produced using a protective gas in a reduced amount or without the use of any protective gas, and a method for producing the magnesium alloy.
A further object of the present invention is to provide a magnesium alloy produced using an additive capable of improving the cleanness of molten magnesium in a melting furnace or during transfer or feeding, and a method for producing the magnesium alloy.
Another object of the present invention is to provide a magnesium alloy that does not encounter the problems of poor flowability, hot cracking, mold sticking, etc. during production to achieve improved casting, forming, welding and powder metallurgy (PM) performance characteristics, and a method for producing the magnesium alloy.
Another object of the present invention is to provide a magnesium alloy produced using a cheap additive and a protective gas in a reduced amount or without the use of any protective gas, thus lowering the production cost, and a method for producing the magnesium aljoy.
Another object of the present invention is to provide a magnesium alloy that uses an additive causing no change in original alloy specification to execute the inherent application of the alloy, and a method for producing the magnesium alloy.
Another object of the present invention is to provide a magnesium alloy whose mechanical properties are improved by grain refinement and internal soundness, and a method for producing the magnesium alloy.
Another object of the present invention is to provide a magnesium alloy with improved welding and joint performance characteristics, and a method for producing the magnesium alloy.
Another object of the present invention is to provide a magnesium alloy with improved resistance to oxidation and ignition that can be safely used in a variety of applications, and a method for producing the magnesium alloy.
Still another object of the present invention is to provide a magnesium alloy with improved recyclability depending on the type of a flux and temperature control during recycling, and a method for producing the magnesium alloy.
[Technical Solution]
In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a magnesium alloy comprising magnesium grains and an additive compound present at grain boundaries defined by the magnesium grains but absent in the magnesium grains.
In an embodiment, the additive compound may be selected from: a compound of magnesium and an alkali metal; a compound of magnesium and an alkaline earth metal; a compound of a constituent material of the magnesium alloy other than magnesium and an alkali metal; and a compound of a constituent material of the magnesium alloy other than magnesium and an alkaline earth metal.
In an embodiment, the magnesium grains may be pure magnesium grains or magnesium alloy grains.
In an embodiment, the additive compound may be present in an amount of 0.0001 to 30 parts by weight, based on 100 parts by weight of the magnesium alloy. In an embodiment, the additive compound may have a size of 0.1 to 500 μm.
In an embodiment, the magnesium alloy may have an ignition temperature of 500 to 1 ,5000C.
In an embodiment, the magnesium alloy may be selected from the group consisting of a casting alloy, a wrought alloy, a creep alloy, a damping alloy, a biodegradable alloy, a powder metallurgy alloy, and mixtures thereof.
In accordance with another aspect of the present invention, there is provided a method for producing a magnesium alloy, the method comprising melting magnesium in a crucible at 600 to 8000C under a protective gas atmosphere to form molten magnesium, adding an additive to the molten magnesium, stirring the molten mixture for 1 to 400 minutes, casting the molten mixture in a mold at 100 to 3000C, and cooling the cast product. In an embodiment, the magnesium may be pure magnesium or a magnesium alloy.
In an embodiment, the additive may be selected from an alkali metal, an alkali metal oxide, an alkali metal compound, an alkaline earth metal, an alkaline earth metal oxide, an alkaline earth metal compound, and mixtures thereof.
In an embodiment, the alkali metal oxide may be selected from sodium oxide, potassium oxide, and a mixture thereof.
In an embodiment, the alkaline earth metal oxide may be selected from beryllium oxide, magnesium oxide, calcium oxide, strontium oxide, and mixtures thereof.
In an embodiment, the alkaline earth metal compound may be selected from calcium carbide (CaC2), calcium cyanamide (CaCN2), calcium carbonate (CaCOs), calcium sulfate hemihydrate (CaSO4), and mixtures thereof.
In an embodiment, the additive may be added in an amount of 0.0001 to 30 parts by weight, based on 100 parts by weight of the magnesium alloy.
In an embodiment, the additive may have a size of 0.1 to 500 μm. In an embodiment, the additive may be added to increase the ignition temperature and hardness of the magnesium alloy and to reduce the required amount of the protective gas.
[Advantageous Effects] The present invention has the following advantageous effects.
The use of the additive increases the ignition temperature of the magnesium alloy and inhibits the oxidation of the magnesium alloy, so that the protective gas categorized as a greenhouse gas can be used in a reduced amount or the need for the use of the protective gas can be eliminated.
Further, the use of the additive can improve the cleanness of the molten magnesium in a melting furnace or during transfer or feeding.
Further, problems such as poor flowability, hot cracking and mold sticking are not encountered in the production of the magnesium alloy so that the casting, forming, welding and powder metallurgy (PM) performance characteristics of the magnesium alloy can be improved.
Further, the use of the cheap additive and the use of the protective gas in a reduced amount or no use of the protective gas can contribute to a reduction in the production cost of the magnesium alloy.
Further, the additive causes no change in the original alloy specification of the magnesium alloy so that the inherent application of the magnesium alloy can be executed.
Further, the use of the additive leads to grain refinement and internal soundness of the magnesium alloy, resulting in an improvement in the mechanical properties of the magnesium alloy.
Further, the use of the additive inhibits the oxidation of the magnesium alloy and increases the ignition temperature of the magnesium alloy, so that the magnesium alloy can be safely used in a variety of applications.
Further, the additive in the form of a compound present in the grain boundaries but absent in the magnesium grains does not respond to a flux supplied and temperature changes during recycling of the magnesium alloy, thus ensuring good recyclability of the magnesium alloy. That is, recycling of the magnesium alloy requires no additional processing for the addition of the additive.
[Description of Drawings] In the figures:
FIG. 1 is a flow chart illustrating a method for producing a magnesium alloy according to the present invention;
FIG. 2 is an image showing the structure of a magnesium alloy produced by a method of the present invention; FIGS. 3 through 8 are images showing the results of electron probe micro analysis (EPMA) for a magnesium alloy produced by a method of the present invention;
FIGS. 9 through 12 are images showing the results of transmission electron microscopy (TEM) for a magnesium alloy produced by a method of the present invention;
FIGS. 13 and 14 are graphs showing the results of protective gas reduction experiments of magnesium alloys produced by a method of the present invention;
FIG. 15 is a graph showing the results of thermogravimetric analysis (TGA) for a magnesium alloy produced by a method of the present invention;
FIGS. 16 and 17 are graphs showing the results of Auger emission spectroscopy (AES) for an AZ91 D magnesium alloy and a magnesium alloy produced by a method of the present invention; FIG. 18 is a graph showing the hardness values of magnesium alloys produced by a method of the present invention at room temperature and high temperatures;
FIG. 19 is a graph showing the ignition temperatures of magnesium alloys produced by a method of the present invention under an ambient atmosphere and under a nitrogen atmosphere;
FIG. 20 is a graph showing the hardness of magnesium alloys produced by a method of the present invention at room temperature;
FIG. 21 is a graph showing the ignition temperatures of magnesium alloys produced by a method of the present invention under an ambient atmosphere and under a nitrogen atmosphere;
FIG. 22 shows surface images of billets of magnesium alloys produced by a method of the present invention;
FIG. 23 is a graph showing the ignition temperatures of magnesium alloys produced by a method of the present invention;
FIG. 24 is a graph showing the hardness of magnesium alloys produced by a method of the present invention;
FIG. 25 shows images of the structures of an AZ91 D magnesium alloy and a magnesium alloy produced by a method of the present invention;
FIG. 26 is a table showing the hardness data of magnesium alloys produced by a method of the present invention;
FIG. 27 is a graph showing the ignition temperature of a magnesium alloy produced by a method of the present invention; FIG. 28 shows images of the structures of an AZ91 D magnesium alloy and a magnesium alloy produced by a method of the present invention;
FIG. 29 is a table showing the hardness data of magnesium alloys produced by a method of the present invention;
FIG. 30 is a graph showing the ignition temperature of a magnesium alloy produced by a method of the present invention;
FIG. 31 is a graph showing the ignition temperatures of magnesium alloys produced by a method of the present invention; FIG. 32 is a graph showing the hardness of magnesium alloys produced by a method of the present invention;
FIGS. 33 and 34 are graphs showing the results of ignition experiments of magnesium alloys produced by a method of the present invention; FIGS. 35 and 36 are graphs showing the results of protective gas reduction experiments of magnesium alloys produced by a method of the present invention;
FIGS. 37 and 38 are graphs showing the results of ignition experiments of magnesium alloys produced by a method of the present invention; and
FIGS. 39 and 40 are surface images of magnesium alloys produced in the absence (FIG. 39) and presence (FIG. 40) of a protective gas, and FIG. 41 is a surface image of a magnesium alloy produced by a method of the present invention. [Best Mode]
Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, such that those skilled in the art can easily practice the present invention. FIG. 1 is a flow chart illustrating a method for producing a magnesium alloy according to the present invention.
As illustrated in FIG. 1 , the method of the present invention comprises the following steps: formation of molten magnesium (S1), addition of an additive (S2), stirring (S3), casting (S4) and cooling (S5). In step S1 , magnesium is put into a crucible and heated to 600 to
8000C under a protective gas atmosphere. As a result, the magnesium is melted to form molten magnesium.
A temperature below 6000C is insufficient to form molten magnesium. Meanwhile, a temperature above 8000C can increase the risk of ignition of the molten magnesium. The protective gas serves to inhibit the ignition of the magnesium. The protective gas is selected from SF6, SO2, CO2, HFC-134a, Novec™612, inert gases, and equivalents thereof. These protective gases may be used alone or as a mixture of two or more thereof. In step S1 , the magnesium may be selected from pure magnesium, magnesium alloys, and equivalents thereof. Examples of the magnesium alloys include, but are not limited to, AZ91 D, AM20, AM30, AM50, AM60, AZ31 , AS41 , AS31 , AS21X, AE42, AE44, AX51 , AX52, AJ50X, AJ52X, AJ62X, MRM 53, MRI230, AM-HP2, Mg-Al, Mg-Al-Re, Mg-Al-Sn, Mg-Zn- Sn, Mg-Si, Mg-Zn-Y, and equivalents thereof.
In step S2, the additive added to the molten magnesium is in the form of a powder.
As the additive, there can be used an alkali metal, an alkali metal oxide, an alkali metal compound, an alkaline earth metal, an alkaline earth metal oxide, an alkaline earth metal compound, or an equivalent thereof. A mixture of these additives may also be used.
The alkali metal oxide may be selected from sodium oxide, potassium oxide and equivalents thereof. These alkali metal oxides may be used alone or as a mixture of two or more thereof. The alkaline earth metal oxide may be selected from beryllium oxide, magnesium oxide, calcium oxide, strontium oxide, and mixtures thereof. The alkaline earth metal compound may be selected from calcium carbide (CaC2), calcium cyanamide (CaCN2), calcium carbonate (CaCO3), calcium sulfate hemihydrate (CaSO4), and mixtures thereof. However, there is no restriction on the kinds of the alkali metal oxide, alkaline earth metal oxide and the alkaline earth metal compound. That is, any material may be used as the additive so long as it can increase the ignition temperature of the magnesium alloy, reduce the oxidation of the magnesium alloy or decrease the required amount of the protective gas.
In step S2, the additive may be added in an amount of 0.0001 to 30 parts by weight, based on 100 parts by weight of the magnesium alloy. If the amount of the additive added is less than 0.0001 parts by weight, the intended effects (i.e. increased ignition temperature, reduced oxidation and decreased amount of the protective gas) of the additive are negligible. Meanwhile, if the amount of the additive added is more than 30 parts by weight, the inherent characteristics of the magnesium or magnesium alloy are not exhibited. The additive may have a size of 1 to 500 μm. It is practically difficult and economically undesirable to prepare the additive in a size smaller than 1 μm. Meanwhile, the additive larger than 500 μm may not react with the molten magnesium.
In step S3, the molten mixture is stirred for 1 to 400 minutes. A stirring time of less than 1 minute does not ensure sufficient mixing of the additive with the molten magnesium, while a stirring time of more than 400 is unnecessary because further improvement of stirring effects is not attained.
In step S3, the additive is present in the form of an intermetallic compound outside the magnesium or magnesium alloy grains, i.e. at grain boundaries defined by the magnesium grains or magnesium alloy grains, rather than inside the magnesium or magnesium alloy grains. That is, the additive is in the form of an additive compound. Specifically, the additive is in the form of: a compound of magnesium and an alkali metal; a compound of magnesium and an alkaline earth metal; a compound of a constituent material of the magnesium alloy other than magnesium and an alkali metal; or a compound of a constituent material of the magnesium alloy other than magnesium and an alkaline earth metal. The other constituent elements (e.g., oxygen, carbon, nitrogen, etc.) of the additive float on the surface of the molten magnesium and are removed by manual or automatic means. In step S4, the molten mixture is cast in a mold at 100 to 3000C.
The mold may be selected from metal molds, ceramic molds, graphite molds and equivalents thereof. The casting may be performed by gravity casting, continuous casting and equivalent processes thereof. However, there is no restriction on the materials of the mold and the casting processes.
In step S5, the cast product is cooled to room temperature, and then the final magnesium alloy (e.g., magnesium alloy ingot) is taken out of the mold. The magnesium alloy produced by the method of the present invention is composed of magnesium grains and an additive compound present at grain boundaries defined by the magnesium grains but absent in the magnesium grains, as will be explained later.
The additive added during production of the magnesium alloy is distinguished from the additive compound present in the final magnesium alloy. The additive compound present in the magnesium alloy is in the form of an intermetallic compound.
FIG. 2 is an image showing the structure of a magnesium alloy 1 produced by the method of the present invention. As shown in FIG. 2, the magnesium alloy 1 comprises magnesium grains 2 and an additive compound 3.
The additive compound 3 is present at grain boundaries defined by the magnesium grains 2 but is absent in the magnesium grains 2. The additive compound 3 is in the form of an intermetallic compound. The magnesium grains 2 may be selected from pure magnesium grains, magnesium alloy grains, and equivalents thereof.
The additive compound 3 may be selected from: a compound of magnesium and an alkali metal; a compound of magnesium and an alkaline earth metal; a compound of a constituent material of the magnesium alloy other than magnesium and an alkali metal; and a compound of a constituent material of the magnesium alloy other than magnesium and an alkaline earth metal.
The additive compound 3 may be present in an amount of 0.0001 to 30 parts by weight, based on 100 parts by weight of the magnesium alloy. The additive compound may have a size of 0.1 to 500 μm. The critical meanings of the numerical limitations in the content and size of the additive compound 3 have been already explained above.
The magnesium alloy 1 of the present invention may have a hardness (HRF) of 40 to 80. However, the hardness of the magnesium alloy 1 may vary depending on various conditions such as processing and annealing. The magnesium alloy 1 has an ignition temperature of 500 to
1 ,5000C, indicating improved ignition resistance. Further, the amount of a protective gas necessary for the production of the magnesium alloy 1 is considerably reduced, as will be explained below.
On the other hand, the magnesium alloy may be selected from the group consisting of a casting alloy, a wrought alloy, a creep alloy, a damping alloy, a biodegradable alloy, a powder metallurgy alloy, and mixtures thereof. There is no restriction on the kind of the casting alloy. For example, the casting alloy may be produced from a mixture of AZ91 D, AM20, AM50 or AM60 and CaX (e.g., CaO, CaC2 or CaCN2).
The wrought alloy may be produced from a mixture of AZ31 or AM30 and CaX.
The creep alloy may be produced from a mixture of Mg-Al or Mg-Al- Re and CaX or SrO or a mixture of Mg-Al-Sn or Mg-Zn-Sn and ,CaX.
The damping alloy may be produced from a mixture of pure Mg, Mg-Si or SiCp/Mg and CaO. The biodegradable alloy may be produced from a mixture of pure
Mg and CaO.
The powder metallurgy alloy may be produced from a mixture of Mg-Zn-(Y) and CaX.
Hereinafter, the present invention will be explained with reference to experimental results in the following examples.
EXAMPLES
(Example 1)
Three AZ91 D magnesium alloys (each 3 kg) were heated to 68O0C to form molten magnesium alloys. Calcium oxide (CaO) powders having a size of < 100 μm, 100-200 μm and 200-500 μm were added to the respective molten magnesium alloys. Each of the calcium oxide powders was used in an amount of one part by weight (30 g). Thereafter, each of the molten mixtures was stirred for 10 minutes, poured into a metal mold, followed by gravity casting. The cast product was cooled. The elemental analysis of the cast product was conducted by an inductively coupled plasma (ICP) method. The powder sizes, target compositions, elemental analysis results by ICP and yields are shown in Table 1. TABLE 1
Figure imgf000019_0001
As can be seen from the results in Table 1 , the yield of the calcium oxide having a size smaller than 100 μm was 45%. That is, 0.45 parts by weight of the calcium oxide was melted in the corresponding molten magnesium. In contrast, the yields of the calcium oxide having a size of 100-200 μm and the calcium oxide having a size of 200-500 μm were drastically lowered to 0.78% and 0.42%, respectively.
FIGS. 3 through 8 are images showing the results of electron probe micro analysis (EPMA) for the magnesium alloy produced by the method of the present invention.
FIG. 3 is a back scattering electron image of the magnesium alloy. As shown in FIG. 3, the magnesium alloy was substantially composed of grains and grain boundaries defined by the grains. FIG. 4 is an image for magnesium, which is indicated by the red areas, and clearly shows that the magnesium was composed of a number of grains and grain boundaries defined by the grains. In FIG. 4, the blue areas indicate the absence of magnesium. FIG. 5 shows the presence of a small amount of aluminum (red areas) in the grain boundaries. FIG. 6 shows the presence of zinc (red areas) in a much smaller amount than aluminum. FIG. 7 shows the presence of a small amount of calcium (red areas) in the grain boundaries. FIG. 8 shows the substantial absence of oxygen.
These results lead to the conclusion that magnesium made up the largest portion of the magnesium alloy and that aluminum, zinc and calcium were present in the grain boundaries. The minor metal elements were substantially in the form of intermetallic compounds. That is, the calcium oxide added to the AZ91 D magnesium alloy was reduced and was present in the form of an aluminum-calcium compound (AI2Ca) in the grain boundaries. Although calcium oxide is more thermodynamically stable than magnesium, the mechanism of the reduction of calcium oxide has not been clearly established. FIGS. 9 through 12 are images showing the results of transmission electron microscopy (TEM) for a magnesium alloy produced by the method of the present invention.
FIG. 9 is a magnified TEM image. The central black area indicates AI2Ca as an aluminum-calcium compound. FIG. 10 is an image of magnesium present in areas other than the area of the aluminum-calcium compound. FIGS. 11 and 12 are images of aluminum and calcium, respectively. These results demonstrate that aluminum and calcium were present in the form of an intermetallic compound in the magnesium grain boundaries. FIGS. 13 and 14 are graphs showing the results of protective gas reduction experiments of magnesium alloys produced by the method of the present invention.
The graphs of FIGS. 13 and 14 were obtained from experiments at 68O0C as a molten metal temperature for die casting and 72O0C indicating an overheated state, respectively.
In FIGS. 13 and 14, "sealed" refers to a state in which ambient air was not introduced, and "unsealed" refers to a state in which ambient air was introduced. As shown in FIG. 13, 1,000 ppm SF6 was necessary to inhibit ignition in the production of AZ91D, AZ91D-0.04wt%CaO and AZ91 D- 0.13wt%CaO in the unsealed state at 68O0C. In contrast, 500 ppm SF6 was necessary to inhibit ignition in the production of AZ91 D and AZ91 D- 0.04wt%CaO, and about 300 ppm SF6 was necessary to inhibit ignition in the production of AZ91 D-0.13wt%CaO in the sealed state. Consequently, the amount of the protective gas necessary to inhibit ignition was decreased with increasing content of the additive at the operation temperature for die casting in the sealed state.
Next, as shown in FIG. 14, 3,200 ppm, 2,000 ppm and 1 ,000 ppm SF6 were necessary to inhibit ignition in the production of AZ91 D, AZ91 D- 0.04wt%CaO and AZ91 D-0.13wt%CaO, respectively, in the unsealed state at 72O0C. In contrast, about 500 ppm SF6 was necessary to inhibit ignition in the production of AZ91D and AZ91D-0.04wt%CaO in the sealed state, and 300 ppm SF6 was necessary to inhibit ignition in the production of AZ91 D-0.13wt%CaO in the sealed state. These results show that the amount of the protective gas necessary to inhibit ignition was decreased with increasing content of the additive in the sealed state even at the overheating temperature. FIG. 15 is a graph showing the results of thermogravimetric analysis (TGA) for a magnesium alloy produced by the method of the present invention.
In FIG. 15, the x axis shows time and the y axis shows an increment in weight (%). The weight of AZ91 D sharply increased with the passage of time, indicating rapid oxidation of the magnesium alloy. In contrast, the weight of AZ91 D-0.14wt%CaO gradually increased with the passage of time, indicating slow oxidation of the magnesium alloy. For example, after 400 minutes, the weight of AZ91 D and AZ91 D-0.14wt%CaO increased to 113% and 101 %, respectively. These results demonstrate that the addition of the additive inhibited the oxidation of the magnesium alloy.
FIGS. 16 and 17 are graphs showing the results of Auger emission spectroscopy (AES) for an AZ91 D magnesium alloy and a magnesium alloy produced by the method of the present invention. In FIG. 16, the x axis shows sputtering time and the y axis shows the atomic contents ration of oxygen detected. About 40 atomic contents ration of oxygen was detected in AZ91 D until about 9 minutes after sputtering, and thereafter, the amount of oxygen detected decreased, indicating that a relatively thick oxide film was formed in AZ91 D. As shown in FIG. 17, about 26 atomic contents ration of oxygen was detected in AZ91 D-0.7wt%CaO until about one minute after sputtering, and thereafter, the amount of oxygen detected decreased, indicating that a relatively thin oxide film was formed in AZ91 D- 0.7wt%CaO.
These results demonstrate that the addition of the additive inhibited the oxidation of the magnesium alloy.
FIG. 18 is a graph showing the hardness values' of AZ91 D magnesium alloys produced by the method of the present invention at room temperature and high temperatures.
As shown in FIG. 18, the hardness of the AZ91 D magnesium alloys containing 0.007-0.41% by weight of calcium oxide increased with increasing calcium oxide content. Specifically, the hardness of the AZ91 D magnesium alloy containing no calcium oxide (CaO) was about 57, and the hardness of the AZ91 D magnesium alloys containing small amounts of calcium oxide increased to 68 at room temperature (250C). The hardness values of the AZ91 D magnesium alloys at 1000C and 15O0C were slightly lower than those of the alloys at room temperature because of poor thermal stability of β phase (MgI7Ah2) at the high temperatures. FIG. 19 is a graph showing the ignition temperature of magnesium alloys produced by the method of the present invention.
As shown in FIG. 19, the ignition temperature of the magnesium alloys increased with increasing content of calcium oxide. Specifically, the ignition temperature of the AZ91 D magnesium alloy under an ambient atmosphere was about 49O0C and that of the AZ91 D magnesium alloy was about 51O0C under a nitrogen atmosphere, whereas the ignition temperatures of the magnesium alloys containing calcium oxide were increased by at least 1000C in proportion to the content of the additive.
(Example 2)
FIG. 20 is a graph showing the hardness of AZ91 D magnesium alloys produced by the method of the present invention at room temperature. As shown in FIG. 20, the hardness values of the AZ91 D magnesium alloys containing different strontium oxide amounts (0.02-0.48 wt%) were increased with increasing strontium oxide content. Specifically, the AZ91 D magnesium alloy containing no strontium oxide had a hardness of about 57 and the AZ91 D magnesium alloy containing a small amount of strontium oxide had a hardness of about 65 at room temperature.
FIG. 21 is a graph showing the ignition temperatures of AZ91 D magnesium alloys produced by the method of the present invention under an ambient atmosphere and under a nitrogen atmosphere.
As shown in FIG. 21 , the ignition temperatures of the AZ91 D magnesium alloy containing no strontium oxide were about 49O0C and 51O0C under an ambient atmosphere and under a nitrogen atmosphere, respectively, while the ignition temperatures of the AZ91 D magnesium alloys containing different amounts of strontium oxide were increased by at least 1000C. (Example 3)
FIG. 22 shows surface images of billets of AZ91 D magnesium alloys for die casting produced by the method of the present invention. As shown in FIG. 22, the surface of the billet of the AZ91D magnesium alloy containing 0.0001 wt% of beryllium oxide was clean without being oxidized or ignited despite the presence of a very small amount of the alkaline earth metal oxide. Further, the surface of the billet of the AZ91 D magnesium alloy containing 0.5 wt% of magnesium oxide was clean without being oxidized or ignited despite the presence of a small amount of the alkaline earth metal oxide.
FIG. 23 is a graph showing the ignition temperatures of AZ91 D magnesium alloys for die casting produced by the method of the present invention. The ignition temperatures of the AZ91 D magnesium alloy containing 0.0001 wt% of beryllium oxide and the AZ91D magnesium alloy containing 0.5 wt% of magnesium oxide were increased due to the presence of the alkaline earth metal oxides, leading to an improvement in mechanical properties and oxidation resistance. FIG. 24 is a graph showing the hardness of AZ91 D magnesium alloys for die casting produced by the method of the present invention.
As shown in FIG. 24, the hardness values of the AZ91 D magnesium alloy containing 0.0001 wt% of beryllium oxide and the AZ91 D magnesium alloy containing 0.5 wt% of magnesium oxide were increased due to the presence of the alkaline earth metal oxides.
(Example 4)
FIG. 25 shows images of the structures of an AZ91 D magnesium alloy containing no additive and an AZ91D magnesium alloy produced by the method of the present invention.
As shown in FIG. 25, there was no significant difference in grain size between the AZ91 D magnesium alloy containing no additive and the AZ91 D magnesium alloy containing 0.007 wt% of calcium cyanamide (CaCN2) as a calcium-based additive. It was confirmed that the presence of the small amount of the additive did not affect the characteristics of the AZ91 D magnesium alloy.
FIG. 26 is a table showing the hardness data of AZ91 D magnesium alloys produced by the method of the present invention. As shown in FIG. 26, the AZ91 D magnesium alloys containing calcium cyanamide as a calcium compound were measured to have an average hardness of about 66, which is about 4 higher than the hardness (about 62) of an AZ91 D magnesium alloy containing no additive.
FIG. 27 is a graph showing the ignition temperature of an AZ91 D magnesium alloy containing no additive and an AZ91 D magnesium alloy produced by the method of the present invention.
As shown in FIG. 27, the ignition temperature of the AZ91 D magnesium alloy containing calcium cyanamide as a calcium compound reached about 54O0C under a nitrogen atmosphere, which is about 3O0C higher than the ignition temperature (51O0C) of the AZ91 D magnesium alloy containing no additive.
(Example 5) FIG. 28 shows images of the structures of an AZ91 D magnesium alloy containing no additive and an AZ91 D magnesium alloy produced by the method of the present invention.
As shown in FIG. 28, there was no significant difference in grain size between the AZ91 D magnesium alloy containing no additive and the AZ91 D magnesium alloy containing 0.03 wt% of calcium carbide (CaC^) as a calcium-based additive.
FIG. 29 is a table showing the hardness data of AZ91 D magnesium alloys produced by the method of the present invention.
As shown in FIG. 29, the AZ91 D magnesium alloys containing calcium carbide as a calcium compound were measured to have an average hardness of about 65.3, which is about 3 higher than the hardness (about 62) of an AZ91 D magnesium alloy containing no additive.
FIG. 30 is a graph showing the ignition temperatures of an AZ91 D magnesium alloy containing no additive and an AZ91 D magnesium alloy produced by the method of the present invention.
As shown in FIG. 30, the ignition temperature of the AZ91 D magnesium alloy containing calcium carbide as a calcium compound reached about 54O0C under a nitrogen atmosphere, which is about 3O0C higher than the ignition temperature (51O0C) of the AZ91 D magnesium alloy containing no additive.
FIG. 31 is a graph showing the ignition temperatures of magnesium alloys produced by the method of the present invention.
As shown in FIG. 31 , the ignition temperatures of the magnesium alloy AZ91 D-0.007wt%CaCN2 containing calcium cyanamide (CaCN2) and the magnesium alloy AZ91 D-0.03wt%CaC2 containing calcium cyanamide (CaCN2) were much higher than the ignition temperature of a pure magnesium alloy AZ91 D, indicating that the magnesium alloys produced by the method of the present invention had better heat resistance. These results lead to the conclusion that the ignition temperatures of the magnesium alloys were dramatically increased due to the presence of the calcium compound.
(Example 6) FIG. 32 is a graph showing the hardness of AM50 magnesium alloys produced by the method of the present invention.
As shown in FIG. 32, the AM50 magnesium alloy containing no calcium oxide, the AM50 magnesium alloy containing about 0.05% by weight of calcium oxide and the AM50 magnesium alloy containing about 0.15% by weight of calcium oxide were found to have hardness values of about 50, indicating that little influence was given to the microstructure and hardness of the magnesium alloys due to the addition of a small amount of calcium oxide.
FIGS. 33 and 34 are graphs showing the results of ignition experiments of AM50 magnesium alloys produced by the method of the present invention.
As shown in FIG. 33, the AM50 magnesium alloy containing no calcium oxide had an ignition temperature of about 57O0C, the AM50 magnesium alloy containing 0.05% by weight of calcium oxide had an ignition temperature of about 5900C, and the AM50 magnesium alloy containing 0.15% by weight of calcium oxide had an ignition temperature of about 61O0C under an ambient atmosphere.
As shown in FIG. 34, the AM50 magnesium alloy containing no calcium oxide had an ignition temperature of about 55O0C, the AM50 magnesium alloy containing 0.05% by weight of calcium oxide had an ignition temperature of about 57O0C, and the AM50 magnesium alloy containing 0.15% by weight of calcium oxide had an ignition temperature of about 64O0C under a nitrogen atmosphere. From these results, it can be seen that the presence of the additive increased the ignition temperature of the magnesium alloys.
(Example 7)
FIGS. 35 and 36 are graphs showing the results of protective gas reduction experiments of magnesium alloys produced by the method of the present invention.
The graphs of FIGS. 35 and 36 were obtained from experiments at 68O0C as a molten metal temperature for die casting and 72O0C indicating an overheated state, respectively.
As shown in FIG. 35, 500 ppm SF6 was necessary to inhibit ignition in the production of AZ31 , AZ31-0.05wt%CaO and AZ31-0.32wt%CaO in the unsealed state at 68O0C. In contrast, about 100 ppm SF6 was necessary to inhibit ignition in the production of AZ31 and AZ31- 0.05wt%CaO, and about 40 ppm SF6 was necessary to inhibit ignition in the production of AZ31-0.32wt%CaO in the sealed state. Consequently, the amount of the protective gas necessary to inhibit ignition was decreased with increasing content of the additive at the operation temperature for die casting in the sealed state.
Next, as shown in FIG. 36, 1 ,000 ppm SF6 was necessary to inhibit ignition in the production of AZ31 , AZ31-0.05wt%CaO and AZ31- 0.32wt%CaO in the unsealed state at 72O0C. In contrast, about 200 ppm, 100 ppm and 40 ppm SF6 were necessary to inhibit ignition in the production of AZ31 , AZ31-0.05wt%CaO and AZ31-0.32wt%CaO, respectively, in the sealed state. These results show that the amount of the protective gas necessary to inhibit ignition was decreased with increasing content of the additive in the sealed state even at the overheating temperature.
FIGS. 37 and 38 are graphs showing the results of ignition experiments of AZ31 magnesium alloy containing no calcium oxide and AZ31 magnesium alloys produced by the method of the present invention.
As shown in FIG. 37, the AZ31 magnesium alloy containing no calcium oxide had an ignition temperature of about 57O0C under an ambient atmosphere, while the AZ31 magnesium alloy containing 0.3% by weight of calcium oxide had an ignition temperature of about 61O0C under an ambient atmosphere. That is, the presence of the additive increased the ignition temperature of the AZ31 magnesium alloy.
As shown in FIG. 38, the AZ31 magnesium alloy containing no calcium oxide had an ignition temperature of about 64O0C under a nitrogen atmosphere, while the AZ31 magnesium alloy containing 0.3% by weight of calcium oxide had an ignition temperature of about 69O0C under a nitrogen atmosphere. That is, the presence of the additive increased the ignition temperature of the AZ31 magnesium alloy.
FIGS. 39 and 40 are surface images of AZ31 magnesium alloys produced in the absence of (FIG. 39) and presence (FIG. 40) of a protective gas, and FIG. 41 is a surface image of a cast sheet of a magnesium alloy produced by the method of the present invention.
As shown in FIG. 39, the AZ31 magnesium alloy produced without the use of any protective gas was ignited and its surface turned black. As shown in FIG. 40, a metal oxide was incorporated into the AZ31 magnesium alloy produced by spraying a protective gas, leaving cracks on the surface of the magnesium alloy.
In contrast, no ignition or cracking occurred in the AZ31 magnesium alloy produced using calcium oxide, as shown in FIG. 41. Although the foregoing embodiments have been described to practice the magnesium alloy and the production method thereof according to the present invention, these embodiments are set forth for illustrative purposes and do not serve to limit the invention. Those skilled in the art will readily appreciate that many modifications and variations can be made, without departing from the spirit and scope of the invention as defined in the appended claims, and such modifications and variations are encompassed within the scope and spirit of the present invention.

Claims

[CLAIMS] [Claim 1 ]
A magnesium alloy comprising magnesium grains, and an additive compound present at grain boundaries defined by the magnesium grains but absent in the magnesium grains.
[Claim 2]
The magnesium alloy according to claim 1 , wherein the additive compound is selected from: a compound of magnesium and an alkali metal; a compound of magnesium and an alkaline earth metal; a compound of a constituent material of the magnesium alloy other than magnesium and an alkali metal; and a compound of a constituent material of the magnesium alloy other than magnesium and an alkaline earth metal.
[Claim 3]
The magnesium alloy according to claim 1 , wherein the magnesium grains are pure magnesium grains or magnesium alloy grains.
[Claim 4]
The magnesium alloy according to claim 1 , wherein the additive compound is present in an amount of 0.0001 to 30 parts by weight, based on 100 parts by weight of the magnesium alloy.
[Claim 5]
The magnesium alloy according to claim 1 , wherein the additive compound has a size of 0.1 to 500 μm.
[Claim 6]
The magnesium alloy according to claim 1 , wherein the magnesium alloy has an ignition temperature of 500 to 1 ,5000C.
[Claim 7] The magnesium alloy according to claim 1 , wherein the magnesium alloy is selected from the group consisting of a casting alloy, a wrought alloy, a creep alloy, a damping alloy, a biodegradable alloy, a powder metallurgy alloy, and mixtures thereof.
[Claim 8]
A method for producing a magnesium alloy, the method comprising melting magnesium in a crucible at 600 to 8000C under a protective gas atmosphere to form molten magnesium, adding an additive to the molten magnesium, stirring the molten mixture for 1 to 400 minutes, casting the molten mixture in a mold at 100 to 3000C, and cooling the cast product.
[Claim 9] The method according to claim 8, wherein the magnesium is pure magnesium or a magnesium alloy.
[Claim 10] The method according to claim 8, wherein the additive is selected from an alkali metal, an alkali metal oxide, an alkali metal compound, an alkaline earth metal, an alkaline earth metal oxide, an alkaline earth metal compound, and mixtures thereof.
[Claim 11 ]
The method according to claim 8, wherein the alkali metal oxide is selected from sodium oxide, potassium oxide, and a mixture thereof.
[Claim 12] The method according to claim 8, wherein the alkaline earth metal oxide is selected from beryllium oxide, magnesium oxide, calcium oxide, strontium oxide, and mixtures thereof.
[Claim 13] The method according to claim 10, wherein the alkaline earth metal compound is selected from calcium carbide (CaC2), calcium cyanamide (CaCN2), calcium carbonate (CaCOs), calcium sulfate hemihydrate (CaSO4), and mixtures thereof.
[Claim 14]
The method according to claim 8, wherein the additive is added in an amount of 0.0001 to 30 parts by weight, based on 100 parts by weight of the magnesium alloy.
[Claim 15]
The method according to claim 8, wherein the additive has a size of 0.1 to 500 μm.
[Claim 16]
The method according to claim 8, wherein the additive is added to increase the ignition temperature and hardness of the magnesium alloy and to reduce the required amount of the protective gas.
PCT/KR2008/005655 2008-09-18 2008-09-24 Magnesium alloy and manufacturing method thereof Ceased WO2010032893A1 (en)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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* Cited by examiner, † Cited by third party
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6719857B2 (en) * 2000-02-24 2004-04-13 Mitsubishi Aluminum Co., Ltd. Die casting magnesium alloy
JP2007002318A (en) * 2005-06-24 2007-01-11 National Institute Of Advanced Industrial & Technology Superplastic magnesium alloy manufacturing method from grain boundary precipitation type magnesium alloy scrap
KR20070096477A (en) * 2006-03-24 2007-10-02 (주)이노캐스트 Heat resistant magnesium alloy

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100614615B1 (en) * 2005-01-21 2006-08-22 주식회사 로코 Keypad manufacturing jig
KR100681539B1 (en) * 2005-02-25 2007-02-12 한국생산기술연구원 Calcium Oxide-Added Magnesium Alloy and Manufacturing Method Thereof
KR100883567B1 (en) * 2007-01-23 2009-02-17 한국생산기술연구원 Magnesium alloy to which strontium oxide is added and its manufacturing method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6719857B2 (en) * 2000-02-24 2004-04-13 Mitsubishi Aluminum Co., Ltd. Die casting magnesium alloy
JP2007002318A (en) * 2005-06-24 2007-01-11 National Institute Of Advanced Industrial & Technology Superplastic magnesium alloy manufacturing method from grain boundary precipitation type magnesium alloy scrap
KR20070096477A (en) * 2006-03-24 2007-10-02 (주)이노캐스트 Heat resistant magnesium alloy

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
HA, S-H. ET AL.: "Effects of CaO and Ca additions on Microstructure and Ignition Resistance of Pure Mg.", JOURNAL OF THE KOREAN FOUNDRYMEN'S SOCIETY., vol. 26, no. 3, June 2006 (2006-06-01), pages 146 - 151 *
HA, S-H. ET AL.: "'Oxidation behavior of CaO added Mg and Mg-Al alloys.' Journal of the Korean Foundrymen's Society.", vol. 27, no. 3, May 2007 (2007-05-01), pages 126 - 130 *
HIRAI, K. ET AL.: "Effects of Ca and Sr addition on mechanical properties of a cast AZ91 magnesium alloy at room and elevated temperature.", MATERIALS SCIENCE & ENGINEERING A., vol. A403, no. ISSUES, 25 August 2005 (2005-08-25), pages 276 - 280 *
LEE, J-K. ET AL.: "Melt Protection Property and Ignition Resistance Property of CaO added AZ91D Mg Alloy.", JOURNAL OF THE KOREAN FOUNDRYMEN'S SOCIETY., vol. 27, no. 3, May 2007 (2007-05-01), pages 131 - 134 *
LI, P. ET AL.: "Microstructure and properties of AZ91D alloy with Ca additions.", MATERIALS LETTERS., vol. 59, no. ISSUE, March 2005 (2005-03-01), pages 671 - 675 *

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