Aluminum-free high-strength heat-resistant die-casting magnesium alloy and preparation method thereof

A high-strength, heat-resistant and pressure-resistant technology, applied in the field of metal materials, can solve problems such as limited weight ratio, achieve low shrinkage and porosity tendency, refine casting structure, and good die-casting performance.

CN101613823AInactive Publication Date: 2009-12-30SHENYANG POLYTECHNIC UNIV
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2009-12-30
Estimated Expiration
Not applicable · inactive patent
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Abstract

The invention provides an aluminum-free high-strength heat-resistant die-casting magnesium alloy. The alloy comprises the following chemical compositions in percentage by weight: 7.5 to 12.5 percent of Gd, 2.5 to 3.5 percent of Y, 0.3 to 1 percent of Zr, 0.5 to 1.5 percent of Zn, less than or equal to 0.02 percent of Si, less than or equal to 0.003 percent of Fe, less than or equal to 0.003 percent of Ni, less than or equal to 0.003 percent of Cu, and the balance of Mg, wherein Si, Fe, Ni and Cu are impurity elements. By adding Gd, Y, Zr and Zn as rare earth elements to magnesium melt, the invention develops the magnesium alloy which is high in strength, high in heat resistance and suitable for die casting. Although the prices of the magnesium alloy is 2 to 3 times that of the common die-casting magnesium alloy, the magnesium alloy has the advantages of good die-casting forming performance, high mechanical properties and good heat resistance, can be used for parts requiring high heat resistance, and has great potential for development.
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Description

technical field

[0001] The invention relates to an aluminum-free high-strength heat-resistant die-casting magnesium alloy and a preparation method thereof, belonging to the field of metal materials. Background technique

[0002] Magnesium alloy is currently the lightest metal structural material in practical application. It has the advantages of low density, high specific strength, excellent machining performance and good shock absorption. It is widely used in aerospace, automobiles and 3C products. At present, the die-casting magnesium alloys used are mainly Mg-Al series, among which the most widely used are AZ and AM series alloys, such as AZ91 alloy (the room temperature strength and toughness indicators are: tensile strength 230MPa, yield strength 140MPa, elongation 3% ; High-temperature strength and toughness indicators: tensile strength at 200°C is 110MPa, yield strength is 60MPa, and elongation is 6%). At present, the application of magnesium alloys in automobiles is...

Examples

Embodiment 1

[0013] Preheat pure magnesium ingots, pure Gd, pure GdY, Mg-Zr master alloy and pure Zn to 150-200°C in the presence of 0.01-0.03% SF 6 and a margin of N 2 The mixed gas protection furnace is melted. First put the pure magnesium ingot into the melting furnace, after it is completely melted, raise the temperature of the melt to 720°C, then add the preheated pure Gd, pure GdY, Mg-Zr master alloy and pure Zn directly into the melt In the middle, after stirring twice, make it evenly mixed, let it stand for 10 minutes, then lower the temperature to 680°C, remove the scum on the surface, and carry out die-casting. During die casting, the injection speed is 2.4m / s, the pouring temperature is 710°C, and the initial mold temperature is 200°C.

[0014] The casting composition that obtains is shown in the following table (by mass percentage):

[0015] Gd

Y

Zr

Zn

Si

Fe

Ni

Cu

Mg

8.1

2.6

0.4

0.7

0.008

0.002

...

Embodiment 2

[0024] Preheat pure magnesium ingots, pure Gd, pure GdY, Mg-Zr master alloy and pure Zn to 150-200°C in the presence of 0.01-0.03% SF 6 and a margin of N 2 The mixed gas protection furnace is melted. First put the pure magnesium ingot into the melting furnace, after it is completely melted, raise the temperature of the melt to 720°C, then add the preheated pure Gd, pure GdY, Mg-Zr master alloy and pure Zn directly into the melt In the middle, after stirring twice, make it evenly mixed, let it stand for 10 minutes, then lower the temperature to 680°C, remove the scum on the surface, and carry out die-casting. During die casting, the injection speed is 2.4m / s, the pouring temperature is 710°C, and the initial mold temperature is 200°C.

[0025] The casting composition that obtains is shown in the following table (by mass percentage):

[0026] Gd

Y

Zr

Zn

Si

Fe

Ni

Cu

Mg

10.0

3.5

0.4

0.5

0.009

0.003

...

Embodiment 3

[0034] Preheat pure magnesium ingots, pure Gd, pure GdY, Mg-Zr master alloy and pure Zn to 150-200°C in the presence of 0.01-0.03% SF 6 and a margin of N 2 The mixed gas protection furnace is melted. First put the pure magnesium ingot into the melting furnace, after it is completely melted, raise the temperature of the melt to 720°C, then add the preheated pure Gd, pure GdY, Mg-Zr master alloy and pure Zn directly into the melt In the middle, after stirring twice, make it evenly mixed, let it stand for 10 minutes, then lower the temperature to 680°C, remove the scum on the surface, and carry out die-casting. During die casting, the injection speed is 2.4m / s, the pouring temperature is 710°C, and the initial mold temperature is 200°C.

[0035] The casting composition that obtains is shown in the following table (by mass percentage):

[0036] Gd

Y

Zr

Zn

Si

Fe

Ni

Cu

Mg

9.2

2.5

0.5

0.6

0.01

0.002

0....