Method for processing magnesium alloy

A processing method and magnesium alloy technology, which is applied in the processing of high-toughness magnesium alloys and new high-strength fields, can solve the problems of increasing the cost of magnesium alloy parts, low yield, and low efficiency of magnesium alloy plastic processing, etc., to achieve fine structure, The effect of improving mechanical properties and eliminating pores

Inactive Publication Date: 2008-07-02
GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, the plastic processing efficiency of magnesium alloy is low, and the yield is also low, which increases the cost of magnesium alloy parts virtually.
The castings produced by the thixoforming technology invented in recent years have the characteristics of fine and uniform structure, and at the same time avoid the phenomena of porosity, shrinkage and thermal cracking, but the oxidation of magnesium particles affects the actual production of this process. application in

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] After the AZ91D alloy is smelted, it is poured into SF 6 and CO 2 Insulate in a constant temperature furnace protected by a mixed gas, keep the melt temperature at 620°C for 10 minutes, and after 2 minutes of electromagnetic stirring, use SF at a low pressure of 0.2-0.3 atmospheres 6 / CO 2 The mixed gas presses the slurry into the cavity, the filling speed is 0.6Kg / s, the mold temperature is 256°C; the filling time is 0.2 minutes, the cavity temperature is 240°C, and pressurization is completed after filling. After the casting is cooled to room temperature, the pressure is removed. Castings were solution treated at 420°C for 18 hours, SO 2 Gas protection, water quenching to room temperature. The aging temperature is 200° C., and the aging time is 8 hours.

[0029] Average grain size: 36.4 μm. (GB / T6394-2002, straight line intercept method, the same below)

[0030] The room temperature mechanical properties of AZ91D alloy as cast are:

[0031] Tensile strength: 2...

Embodiment 2

[0035] After the AZ91D alloy is smelted, it is poured into SF 6 / CO 2 Keep warm in a gas-protected constant temperature furnace, keep the melt temperature at 620°C for 15 minutes, and after 2 minutes of electromagnetic stirring, use low-pressure SF 6 / CO 2 The mixed gas presses the slurry into the cavity, the filling speed is 0.2Kg / s, the mold temperature is 250°C; the filling time is 0.2 minutes, the cavity temperature is 240°C, and pressurization is completed after filling. After the casting is cooled to room temperature, the pressure is removed. Castings were solution treated at 420°C for 18 hours, SO 2 Gas protection, water quenching to room temperature. The aging temperature is 200° C., and the aging time is 8 hours.

[0036] Average grain size: 35.8 μm.

[0037] The room temperature mechanical properties of AZ91D alloy as cast are:

[0038] Tensile strength: 278MPa, yield strength: 172MPa, elongation: 6.8%. The room temperature T6 mechanical properties of AZ91D a...

Embodiment 3

[0041] After the AZ91D alloy is smelted, it is poured into SF 6 / CO 2 Keep warm in a gas-protected constant temperature furnace, keep the melt temperature at 600°C for 10 minutes, and after 2 minutes of electromagnetic stirring, use low-pressure SF 6 / CO 2 The mixed gas presses the slurry into the cavity, the filling speed is 0.4Kg / s, the mold temperature is 280°C; the filling time is 0.2 minutes, the cavity temperature is 240°C, and pressurization is completed after filling. After the casting is cooled to room temperature, the pressure is removed. Castings were solution treated at 420°C for 18 hours, SO 2Gas protection, water quenching to room temperature. The aging temperature is 200° C., and the aging time is 8 hours.

[0042] Average grain size: 32.7 μm.

[0043] The room temperature mechanical properties of AZ91D alloy as cast are:

[0044] Tensile strength: 292MPa, yield strength: 205MPa, elongation: 6.5%.

[0045] The room temperature T6 mechanical properties of...

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Abstract

A magnesium alloy processing method comprises the following steps: (1) smelting a magnesium alloy, pouring into a constant-temperature furnace containing a SF6 / CO2 protection gas to maintain the temperature of the molten alloy at 620 to 580 DEG C for 10 to 15 min; (2) electromagnetically stirring, and pressing the slurry material obtained in the step (1) by a mixture gas containing SF6 and CO2 with 0.2 to 0.3 atmospheric pressure into a cavity with a temperature of 240 to 260 DEG C for filling a mold with a temperature of 250 to 280 DEG C at a speed of 0.2 to 0.6 Kg / s for 0.2 to 0.4 min; and (3) compressing to 100 to 150 MPa and relieving the pressure when a cast is solidified. By combining semi-solid state and high-pressure solidification means, the inventive method can effectively thin magnesium alloy part tissue and eliminate air holes, porosity, component segregation and hot tearing susceptibility by twice nucleation in the solidification process. The mechanical property of the magnesium parts formed by the method is significantly improved in comparison with conventional die-casting process, and subsequent heat aging treatment can be carried out.

Description

technical field [0001] The invention relates to a processing method of a novel high-strength and high-toughness magnesium alloy. The invention belongs to the field of material processing. Background technique [0002] Magnesium alloy is currently the lightest structural metal, with a density of about 3 / 5 of aluminum and 1 / 4 of steel. Magnesium alloy also has many advantages such as good electrical and thermal conductivity and electromagnetic shielding. Magnesium alloy parts have been used in the automotive industry and electronic communication products to a certain extent. However, due to their low strength, magnesium alloy parts have limited their further application in industry, especially in the automotive industry. [0003] At present, deformation and adding a large amount of rare earth elements are mainly used to improve the mechanical properties of magnesium alloys. These two methods cannot be adapted to large-scale industrial production due to high cost and low yiel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C23/00C22C1/02B22D21/04B22D17/00B22D18/02B22D27/04C22F1/06
Inventor 邹宏辉李德富马志新沈健
Owner GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG
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