High-strength cast magnesium alloy and preparation method thereof

A technology for casting magnesium alloys with high strength, applied in the field of metal materials, can solve the problems of low thermal stability of magnesium alloy grains, difficult to control the amount of Zr, low absorption rate of Zr, etc., achieves good recession resistance, reduces inclusions, The effect of high melting point

Active Publication Date: 2012-07-04
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Although Zr is an excellent refining agent for magnesium alloys, there are some disadvantages in refining magnesium alloys by adding Mg-Zr master alloys.
Firstly, the production process of the Mg-Zr master alloy is complicated and the energy consumption is high, which leads to the expensive price of the master alloy; secondly, the density of Zr (6.52g / cm 3 ) is much greater than the density of the magnesium melt, the undissolved Zr particles quickly sink to the bottom of the crucible, and the Zr particles with a size larger than 5 μm cannot be used as heterogeneous nucleation cores, resulting in a low absorption rate of Zr in the master alloy. The amount of Zr actually obtained in the alloy is difficult to control; moreover, the thermal stability of the magnesium alloy grains refined by the Mg-Zr master alloy is low, and it is easy to grow up during the high-temperature solid solution process

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] The components and mass percentages of the high-strength cast magnesium alloy are: 8wt.%Gd, 5wt.%Y, 0.6wt.%Al, the content of impurity elements Si, Fe, Cu and Ni is less than 0.02wt.%. The amount is Mg (wt.% refers to the percentage of the components in the total mass of the prepared magnesium alloy, and the total mass is the sum of the mass of Mg, Al and various master alloys).

[0043] The preparation method of the magnesium alloy includes two process steps of smelting and subsequent heat treatment.

[0044] Among them, the previous smelting process is in SF 6 and CO 2 Under the condition of mixed gas protection, the steps are as follows:

[0045] (1) Baking material: Preheat pure magnesium, pure aluminum, intermediate alloys Mg-Gd and Mg-Y for more than 3 hours to 180°C;

[0046] (2) Molten magnesium: Put the dried pure magnesium into the SF 6 / CO 2 Melting in a gas shielded crucible resistance furnace;

[0047] (3) Adding Gd and Y: When the temperature of the ...

Embodiment 2

[0055] The components and mass percentages of the high-strength cast magnesium alloy are: 12wt.% Gd, 2wt.% Y, 1.3wt.% Al, and the content of impurity elements Si, Fe, Cu and Ni is less than 0.02wt.%. The amount is Mg.

[0056] The preparation method of the magnesium alloy includes two process steps of smelting and subsequent heat treatment.

[0057] Among them, the previous smelting process is in SF 6 and CO 2 Under the condition of mixed gas protection, the steps are as follows:

[0058] (1) Baking material: Preheat pure magnesium, pure aluminum, intermediate alloys Mg-Gd and Mg-Y for more than 3 hours to 225°C;

[0059] (2) Molten magnesium: Put the dried pure magnesium into the SF 6 / CO 2 Melting in a gas shielded crucible resistance furnace;

[0060] (3) Adding Gd and Y: When the temperature of the magnesium liquid reaches 730°C, directly add the master alloy Mg-Gd to the magnesium liquid, the master alloy is Mg-25wt.%Gd, that is, Gd accounts for 25wt in the master a...

Embodiment 3

[0068] The components and mass percentages of the high-strength cast magnesium alloy are: 14wt.% Gd, 1wt.% Y, 2wt.% Al, the content of impurity elements Si, Fe, Cu and Ni is less than 0.02wt.%, and the balance for Mg.

[0069] The preparation method of the magnesium alloy includes two process steps of smelting and subsequent heat treatment.

[0070] Among them, the previous smelting process is in SF 6 and CO 2 Under the condition of mixed gas protection, the steps are as follows:

[0071] (1) Baking material: Preheat pure magnesium, pure aluminum, intermediate alloys Mg-Gd and Mg-Y for more than 3 hours to 250°C;

[0072] (2) Molten magnesium: Put the dried pure magnesium into the SF 6 / CO 2 Melting in a gas shielded crucible resistance furnace;

[0073] (3) Adding Gd and Y: When the temperature of the magnesium liquid reaches 740°C, directly add the master alloy Mg-Gd into the magnesium liquid, the master alloy is Mg-25wt.%Gd, that is, Gd accounts for 25wt in the master...

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Abstract

The invention discloses high-strength cast magnesium alloy and a preparation method thereof. The high-strength cast magnesium alloy comprises the following ingredients by mass percentage: 8 to 14 weight percent of Gd, 1 to 5 weight percent of Y, 0.6 to 2 weight percent of Al, less than 0.02 weight percent of impurity elements of Si, Fe, Cu and Ni and the balance of Mg. The preparation method of magnesium alloy comprises two process work procedures: smelting and subsequent heat treatment, wherein the smelting process work procedure is carried out under the protection condition of SF6 and CO2 mixed gas and comprises the steps of material baking, magnesium melting, Gd and Y addition, Al addition and casting, and the heat treatment process work procedure comprises solid solution treatment andaging treatment. Through the method of adding rare earth elements such as Al, Gd and Y into the alloy to generate Al-RE intermetallic compounds through in-situ reaction, the goal of refining crystalline grains is reached, the crystalline grain stability of the obtained high-strength cast magnesium alloy is excellent, the recession resistance performance of the refining effect is high, and higher tensile strength and elongation are realized.

Description

technical field [0001] The invention relates to a magnesium alloy and a preparation method thereof, in particular to a high-strength casting rare earth magnesium alloy and a preparation method thereof, belonging to the technical field of metal materials. Background technique [0002] As the lightest metal structural material, magnesium alloy has the advantages of high specific strength and specific stiffness. In recent years, due to the gradual adoption of magnesium alloy components in the automotive and electronics industries, the application of magnesium alloys has been promoted. However, compared with aluminum alloys, there is still a big gap in the application of magnesium alloys, mainly due to insufficient strength, poor heat resistance and poor corrosion resistance. Adding rare earth elements is an effective method to improve the strength, heat resistance and corrosion resistance of magnesium alloys, such as rare earth magnesium alloys such as WE54 and WE43. Recent s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C23/06C22C1/03C22F1/06
Inventor 戴吉春吴国华刘文才孙明丁文江
Owner SHANGHAI JIAO TONG UNIV
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