High-strength cast magnesium alloy and preparation method thereof

Abstract

The invention relates to a high-strength cast magnesium alloy. The high-strength cast magnesium alloy is an Mg-Bi-Al-Zn-Sr alloy and comprises components in percentage by weight as follows: 3wt%-8.0wt% of Bi, 0.5wt%-4.0wt% of Al, 0.1wt%-1.0wt% of Zn, 0.05wt%-0.15wt% of Sr and the balance of Mg. The Bi element is used as a main alloy element, a large quantity of Mg3Bi2 phases are formed through simple alloying means, a small quantity of aluminum and zinc elements are used for improving the strength of the alloy, so that the high-strength cast magnesium alloy is developed from the alloy series, and the alloy has the tensile strength of 276-296 MPa, the yield strength of 155-170 MPa and the elongation of 5.3%-7.3% and has mechanical properties comparable with those of rear earth magnesium alloys.

Description

technical field

[0001] The invention relates to a non-rare earth low-cost high-strength cast magnesium alloy and a preparation method thereof, in particular to a Mg-Bi-Al-Zn-Sr alloy and a preparation method thereof, belonging to the field of metal materials and metallurgy. Background technique

[0002] Magnesium alloy is currently the lightest metal engineering structure material in practical application, and the density of pure magnesium is about 1.74g / cm 3 , its density is about 1 / 4 of steel, 1 / 3 of zinc, and 2 / 3 of aluminum alloy. Magnesium alloys have the characteristics of high specific strength, excellent mechanical cutting performance and damping and shock absorption performance, which meet the urgent needs of the modern automobile industry for weight reduction and environmental protection. Since the 1980s, with the rapid development of the automobile industry, a large number of magnesium alloy materials have been used in automobile parts, among which the commercial...

Examples

Embodiment 1

[0035] (1) Take raw material by the mass percent of alloy Mg-3.8Bi-3.2Al-0.5Zn-0.05Sr (wt%): pure Bi, pure Al, pure Zn and Mg-5Sr master alloy, all the other are Mg (per 1000 The gram target alloy can be prepared by 10 grams of Mg-5Sr, 32 grams of Al, 5 grams of Zn, 38 grams of Bi and 917 grams of Mg); and do a good job of surface treatment of raw materials (such as removing dirt, scale, etc.).

[0036] (2) First clean the melting furnace and heat it to 450°C, put the magnesium ingot preheated to 200°C into the crucible of the melting furnace, set the furnace temperature to 720°C, and slowly heat the heating rate to 20-40°C / min And maintain the set furnace temperature.

[0037] (3) After the pure magnesium ingots are completely melted, respectively add pure Bi, pure Al, pure Zn and Mg-5Sr intermediate alloys preheated to about 200°C to the magnesium melt, raise the furnace temperature to 730°C, and keep warm 5 to 10 minutes, then mechanically stirred for 3 to 5 minutes, then ...

Embodiment 2

[0042] (1) Take raw material by the mass percent of alloy Mg-6Bi-2.0Al-0.6Zn-0.08Sr (wt%): pure Bi, pure Al, pure Zn and Mg-5Sr master alloy, all the other are Mg; And do well Surface treatment of raw materials (such as removal of dirt, scale, etc.).

[0043] (2) First clean the melting furnace and heat it to 450°C, put the magnesium ingot preheated to 200°C into the crucible of the melting furnace, set the furnace temperature to 720°C, and slowly heat the heating rate to 20-40°C / min And maintain the set furnace temperature.

[0044] (3) After the pure magnesium ingots are completely melted, respectively add pure Bi, pure Al, pure Zn and Mg-5Sr intermediate alloys preheated to about 200°C to the magnesium melt, raise the furnace temperature to 730°C, and keep warm 5 to 10 minutes, then mechanically stirred for 3 to 5 minutes, then filled with argon for refining and degassing, then adjusted the furnace temperature to the pouring temperature of 720°C, stood for 2 to 10 minutes,...

Embodiment 3

[0049] (1) Take raw material by the mass percent of alloy Mg-7.0Bi-1.0Al-1.0Zn-0.08Sr (wt%): pure Bi, pure Al, pure Zn and Mg-5Sr master alloy, all the other are Mg; And do Good raw material surface treatment (such as removal of dirt, scale, etc.).

[0050] (2) First clean the melting furnace and heat it to 450°C, put the magnesium ingot preheated to 200°C into the crucible of the melting furnace, set the furnace temperature to 720°C, and slowly heat the heating rate to 20-40°C / min And maintain the set furnace temperature.

[0051] (3) After the pure magnesium ingots are completely melted, respectively add pure Bi, pure Al, pure Zn and Mg-5Sr intermediate alloys preheated to about 200°C to the magnesium melt, raise the furnace temperature to 730°C, and keep warm 5 to 10 minutes, then mechanically stirred for 3 to 5 minutes, then filled with argon for refining and degassing, then adjusted the furnace temperature to the pouring temperature of 720°C, stood for 2 to 10 minutes, a...

technical field

[0001] The invention relates to a non-rare earth low-cost high-strength cast magnesium alloy and a preparation method thereof, in particular to a Mg-Bi-Al-Zn-Sr alloy and a preparation method thereof, belonging to the field of metal materials and metallurgy. Background technique

[0002] Magnesium alloy is currently the lightest metal engineering structure material in practical application, and the density of pure magnesium is about 1.74g / cm 3 , its density is about 1 / 4 of steel, 1 / 3 of zinc, and 2 / 3 of aluminum alloy. Magnesium alloys have the characteristics of high specific strength, excellent mechanical cutting performance and damping and shock absorption performance, which meet the urgent needs of the modern automobile industry for weight reduction and environmental protection. Since the 1980s, with the rapid development of the automobile industry, a large number of magnesium alloy materials have been used in automobile parts, among which the commercial...

Examples

Embodiment 1

[0035] (1) Take raw material by the mass percent of alloy Mg-3.8Bi-3.2Al-0.5Zn-0.05Sr (wt%): pure Bi, pure Al, pure Zn and Mg-5Sr master alloy, all the other are Mg (per 1000 The gram target alloy can be prepared by 10 grams of Mg-5Sr, 32 grams of Al, 5 grams of Zn, 38 grams of Bi and 917 grams of Mg); and do a good job of surface treatment of raw materials (such as removing dirt, scale, etc.).

[0036] (2) First clean the melting furnace and heat it to 450°C, put the magnesium ingot preheated to 200°C into the crucible of the melting furnace, set the furnace temperature to 720°C, and slowly heat the heating rate to 20-40°C / min And maintain the set furnace temperature.

[0037] (3) After the pure magnesium ingots are completely melted, respectively add pure Bi, pure Al, pure Zn and Mg-5Sr intermediate alloys preheated to about 200°C to the magnesium melt, raise the furnace temperature to 730°C, and keep warm 5 to 10 minutes, then mechanically stirred for 3 to 5 minutes, then ...

Embodiment 2

[0042] (1) Take raw material by the mass percent of alloy Mg-6Bi-2.0Al-0.6Zn-0.08Sr (wt%): pure Bi, pure Al, pure Zn and Mg-5Sr master alloy, all the other are Mg; And do well Surface treatment of raw materials (such as removal of dirt, scale, etc.).

[0043] (2) First clean the melting furnace and heat it to 450°C, put the magnesium ingot preheated to 200°C into the crucible of the melting furnace, set the furnace temperature to 720°C, and slowly heat the heating rate to 20-40°C / min And maintain the set furnace temperature.

[0044] (3) After the pure magnesium ingots are completely melted, respectively add pure Bi, pure Al, pure Zn and Mg-5Sr intermediate alloys preheated to about 200°C to the magnesium melt, raise the furnace temperature to 730°C, and keep warm 5 to 10 minutes, then mechanically stirred for 3 to 5 minutes, then filled with argon for refining and degassing, then adjusted the furnace temperature to the pouring temperature of 720°C, stood for 2 to 10 minutes,...

Embodiment 3

[0049] (1) Take raw material by the mass percent of alloy Mg-7.0Bi-1.0Al-1.0Zn-0.08Sr (wt%): pure Bi, pure Al, pure Zn and Mg-5Sr master alloy, all the other are Mg; And do Good raw material surface treatment (such as removal of dirt, scale, etc.).

[0050] (2) First clean the melting furnace and heat it to 450°C, put the magnesium ingot preheated to 200°C into the crucible of the melting furnace, set the furnace temperature to 720°C, and slowly heat the heating rate to 20-40°C / min And maintain the set furnace temperature.

[0051] (3) After the pure magnesium ingots are completely melted, respectively add pure Bi, pure Al, pure Zn and Mg-5Sr intermediate alloys preheated to about 200°C to the magnesium melt, raise the furnace temperature to 730°C, and keep warm 5 to 10 minutes, then mechanically stirred for 3 to 5 minutes, then filled with argon for refining and degassing, then adjusted the furnace temperature to the pouring temperature of 720°C, stood for 2 to 10 minutes, a...

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