High-strength and high-modulus casting Mg-RE alloy and preparation method thereof

Abstract

The invention provides a high-strength and high-modulus casting Mg-RE alloy and a preparation method thereof. The Mg-RE alloy comprises 2-4wt% of Nd, 1-3wt% of Li, 0.2-0.6wt% of Zn, 2-4wt% of Al, the balance of Mg and inevitable impurities, wherein the total content of Si, Fe, Cu and Ni in the impurities is smaller than 0.02wt%. The preparation method of the Mg-RE alloy includes the sequential steps of vacuum melting and heat treatment. Compared with the prior art, the preparation method has the advantages that the components of the alloy and the heat treatment process are optimized, the optimized alloy component proportion of the alloy is obtained by studying different component proportions of the alloy elements of Nd, Zn, Li and Al, and therefore compared with an existing alloy, the alloy has the better overall performance of room-temperature strength and elasticity modulus under the component proportion and the heat treatment process.

Description

Technical field

[0001] The invention relates to a magnesium alloy and a preparation method thereof, in particular to a high-strength and high-mode cast magnesium rare earth alloy and a preparation method thereof, and belongs to the technical field of metal materials. Background technique

[0002] Magnesium alloy is currently the lightest metal structural material in practical applications. It has the advantages of low density, high specific strength and specific rigidity, and excellent machining performance. It has a very broad application prospect in the automotive, aerospace and other fields. In recent years, the speed of aerospace and transportation has become higher and higher, the required power is increasing, the stability of components is required to be high and reliable, and higher requirements are put forward for the rigidity and elastic deformation resistance of magnesium alloys. . At the same time, most of the aerospace magnesium alloy parts are produced by casting me...

Examples

preparation example Construction

[0026] On the other hand, the present invention also provides a method for preparing the above-mentioned magnesium alloy, which includes two steps of vacuum melting and heat treatment in sequence.

[0027] As a preferred solution, the vacuum melting step is performed in CO 2 And SF 6 Under the protection of mixed gas (ratio 100:1), it includes the following operations:

[0028] After mixing the ingredients according to the stoichiometric ratio of the elements in the magnesium alloy, preheat the pure Mg, pure Al, pure Zn and the master alloy Mg-Nd at 180~220℃ for more than 2 hours;

[0029] After the preheated pure Mg is melted, pure Zn is added to melt at 670~690℃, the temperature is raised to 720~740, and Mg-Nd master alloy is added for melting. When the melt temperature rises to 720~740℃, pure Zn is added. Al, stir after pure Al is completely melted. After stirring, add pure Li at 700~740℃. After pure Li is completely melted, heat the melt to 780~800℃ for 20~30min and then cool to ...

Embodiment 1

[0034] The components and mass percentages of the high-strength and high-mold cast magnesium rare earth alloy in this embodiment are: 4wt.%Nd, 0.6wt.%Zn, 3wt.%Li, 4wt.%Al, impurity elements Si, Fe, Cu and The total amount of Ni is less than 0.02wt.%, and the balance is Mg.

[0035] The preparation method of the magnesium alloy includes two process steps of smelting and subsequent heat treatment.

[0036] Among them, the previous smelting process is in CO 2 And SF 6 Under the protection of mixed gas (ratio 100:1), the steps are as follows:

[0037] (1) Material preparation: according to the element ratio of the magnesium rare earth alloy of this embodiment, weigh pure Mg, pure Zn, pure Al, pure Li and master alloy Mg-Nd, among which the content of Nd in master alloy Mg-Nd Is 25wt%;

[0038] (2) Baking material: Preheat pure Mg, pure Zn, pure Al, master alloy Mg-Nd at 220℃ for more than 2 hours, pure Li does not need to be preheated;

[0039] (3) Molten magnesium: use a crucible resista...

Embodiment 2

[0048] The composition and mass percentage of the high-strength and high-mold casting magnesium rare earth alloy in this embodiment are: 2wt.%Nd, 0.4wt.%Zn, 2wt.%Li, 3wt.%Al, and impurity elements Si, Fe, Cu and The total amount of Ni is less than 0.02wt.%, and the balance is Mg (wt.% refers to the percentage of the total mass of the prepared magnesium alloy, the total mass is Mg, Zn, Al, Li and Mg-Nd master alloy Quality and).

[0049] The preparation method of the magnesium alloy includes two process steps of smelting and subsequent heat treatment.

[0050] Among them, the previous smelting process is in CO 2 And SF 6 Under the protection of mixed gas (ratio 100:1), the steps are as follows:

[0051] (1) Material preparation: according to the element ratio of the magnesium rare earth alloy of this embodiment, weigh pure Mg, pure Zn, pure Al, pure Li and master alloy Mg-Nd, among which the content of Nd in master alloy Mg-Nd Is 25wt%;

[0052] (2) Baking material: Preheat pure Mg, ...

Technical field

[0001] The invention relates to a magnesium alloy and a preparation method thereof, in particular to a high-strength and high-mode cast magnesium rare earth alloy and a preparation method thereof, and belongs to the technical field of metal materials. Background technique

[0002] Magnesium alloy is currently the lightest metal structural material in practical applications. It has the advantages of low density, high specific strength and specific rigidity, and excellent machining performance. It has a very broad application prospect in the automotive, aerospace and other fields. In recent years, the speed of aerospace and transportation has become higher and higher, the required power is increasing, the stability of components is required to be high and reliable, and higher requirements are put forward for the rigidity and elastic deformation resistance of magnesium alloys. . At the same time, most of the aerospace magnesium alloy parts are produced by casting me...

Examples

preparation example Construction

[0026] On the other hand, the present invention also provides a method for preparing the above-mentioned magnesium alloy, which includes two steps of vacuum melting and heat treatment in sequence.

[0027] As a preferred solution, the vacuum melting step is performed in CO 2 And SF 6 Under the protection of mixed gas (ratio 100:1), it includes the following operations:

[0028] After mixing the ingredients according to the stoichiometric ratio of the elements in the magnesium alloy, preheat the pure Mg, pure Al, pure Zn and the master alloy Mg-Nd at 180~220℃ for more than 2 hours;

[0029] After the preheated pure Mg is melted, pure Zn is added to melt at 670~690℃, the temperature is raised to 720~740, and Mg-Nd master alloy is added for melting. When the melt temperature rises to 720~740℃, pure Zn is added. Al, stir after pure Al is completely melted. After stirring, add pure Li at 700~740℃. After pure Li is completely melted, heat the melt to 780~800℃ for 20~30min and then cool to ...

Embodiment 1

[0034] The components and mass percentages of the high-strength and high-mold cast magnesium rare earth alloy in this embodiment are: 4wt.%Nd, 0.6wt.%Zn, 3wt.%Li, 4wt.%Al, impurity elements Si, Fe, Cu and The total amount of Ni is less than 0.02wt.%, and the balance is Mg.

[0035] The preparation method of the magnesium alloy includes two process steps of smelting and subsequent heat treatment.

[0036] Among them, the previous smelting process is in CO 2 And SF 6 Under the protection of mixed gas (ratio 100:1), the steps are as follows:

[0037] (1) Material preparation: according to the element ratio of the magnesium rare earth alloy of this embodiment, weigh pure Mg, pure Zn, pure Al, pure Li and master alloy Mg-Nd, among which the content of Nd in master alloy Mg-Nd Is 25wt%;

[0038] (2) Baking material: Preheat pure Mg, pure Zn, pure Al, master alloy Mg-Nd at 220℃ for more than 2 hours, pure Li does not need to be preheated;

[0039] (3) Molten magnesium: use a crucible resista...

Embodiment 2

[0048] The composition and mass percentage of the high-strength and high-mold casting magnesium rare earth alloy in this embodiment are: 2wt.%Nd, 0.4wt.%Zn, 2wt.%Li, 3wt.%Al, and impurity elements Si, Fe, Cu and The total amount of Ni is less than 0.02wt.%, and the balance is Mg (wt.% refers to the percentage of the total mass of the prepared magnesium alloy, the total mass is Mg, Zn, Al, Li and Mg-Nd master alloy Quality and).

[0049] The preparation method of the magnesium alloy includes two process steps of smelting and subsequent heat treatment.

[0050] Among them, the previous smelting process is in CO 2 And SF 6 Under the protection of mixed gas (ratio 100:1), the steps are as follows:

[0051] (1) Material preparation: according to the element ratio of the magnesium rare earth alloy of this embodiment, weigh pure Mg, pure Zn, pure Al, pure Li and master alloy Mg-Nd, among which the content of Nd in master alloy Mg-Nd Is 25wt%;

[0052] (2) Baking material: Preheat pure Mg, ...

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