Combined processing method for preparing anti-corrosion AZ91D magnesium alloy with obdurability

A combined processing and magnesium alloy technology, applied in the field of alloy processing, can solve problems such as poor corrosion resistance, and achieve the effects of improving the film forming process, increasing the yield and good industrial application prospects.

Inactive Publication Date: 2013-10-30
HOHAI UNIV +1
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0011] The object of the present invention is to provide a combined processing method for preparing strong, tough and corrosion-resistant AZ91D magnesium alloy with simple process operation and equipment requirements, thereby improving the strength and toughness of the alloy without changing the shape and size of the test piece, and solving its corrosion resistance The problem of poor performance, improve its yield

Method used

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  • Combined processing method for preparing anti-corrosion AZ91D magnesium alloy with obdurability
  • Combined processing method for preparing anti-corrosion AZ91D magnesium alloy with obdurability
  • Combined processing method for preparing anti-corrosion AZ91D magnesium alloy with obdurability

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] The as-cast Mg-9.05wt.%Al-0.65wt.%Zn alloy was processed into a columnar specimen of 19.5mm×19.5mm×40mm by wire cutting. The as-cast microstructure was mainly composed of α(Mg) matrix and interdendritic structures. Network distribution of Mg 17 Al 12 (β) phase composition (see figure 1 (a)). The β phase exists in two forms, one is the coarse bulk β phase, and the other is the fine lamellar β phase in the (α+β) eutectic structure. The surface of the cut specimen was pretreated, and then placed in the mold and heated to 250 °C for 10 min with the furnace, and then pressure was applied for 16 consecutive passes of ECAP extrusion, and the specimen was rotated 180° between adjacent extrusion passes. (i.e. the traditional C path) to improve the uniformity of the extrusion structure, the alloy structure is significantly refined after processing (see figure 1 (b)). The yield strength and tensile strength of Mg-9.05wt.%Al-0.65wt.%Zn alloy are greatly improved after ECAP pro...

Embodiment 2

[0039] The as-cast Mg-9.05wt.%Al-0.65wt.%Zn alloy was processed into a columnar specimen of 19.5mm×19.5mm×40mm by wire cutting. The as-cast microstructure was mainly composed of α(Mg) matrix and interdendritic structures. Network distribution of Mg 17 Al 12 (β) phase composition (see figure 1 ). The β phase exists in two forms, one is the coarse bulk β phase, and the other is the fine lamellar β phase in the (α+β) eutectic structure. The surface of the cut specimen was pretreated, and then placed in the mold and heated to 250 °C for 10 minutes, and then pressure was applied for 12 consecutive passes of ECAP extrusion, and the specimen was rotated 180° between adjacent extrusion passes. (i.e. the traditional C path) to improve the uniformity of the extrusion structure, the alloy structure is significantly refined after processing (see Figure 8 ). After the Mg-9.05wt.%Al-0.65wt.%Zn alloy was processed by ECAP for 12 passes, the yield strength was 133.43MPa and the tensile ...

Embodiment 3

[0041] The as-cast Mg-9.05wt.%Al-0.65wt.%Zn alloy was processed into a columnar specimen of 19.5mm×19.5mm×40mm by wire cutting. The as-cast microstructure was mainly composed of α(Mg) matrix and interdendritic structures. Network distribution of Mg 17 Al 12 (β) phase composition (see figure 1 ). The β phase exists in two forms, one is the coarse bulk β phase, and the other is the fine lamellar β phase in the (α+β) eutectic structure. The surface of the cut specimen was pretreated, and then placed in the mold and heated to 250 °C for 10 min with the furnace, and then pressure was applied for 8 consecutive ECAP extrusions, and the specimen was rotated 180° between adjacent extrusion passes. (i.e. the traditional C path) to improve the uniformity of the extrusion structure, the alloy structure is elongated after processing, and the grains are significantly refined (see Figure 13 ). After 8 passes of ECAP processing, the Mg-9.05wt.%Al-0.65wt.%Zn alloy has a yield strength of...

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Abstract

The invention discloses a combined processing method for preparing an anti-corrosion AZ91D magnesium alloy with obdurability. The combined processing method comprises the following steps: step 1, continuous ECAP (Equal Channel Angular Pressing), wherein the step 1 specifically comprises the substeps of: cutting a casting state AZ91D magnesium alloy blocky material into columnar test pieces, uniformly coating a solid lubricant on the surfaces of the test pieces after a regular pre-treatment and on a surface of a mould, putting the test pieces into the mould to be heated to 230 DEG C to 300 DEG C along with the furnace for heat preservation, then continuously performing ECAP deformation for multiple times, and rotating the test pieces for 180 DEG between two adjacent pressing passes to realize ultrafine processing of the alloy tissues; step 2, subsequent micro-arc oxidation surface treatment, wherein the step 2 specifically comprises the substeps of: cutting the test pieces obtained in the step 1 to obtain a shape needed by a member, performing the micro-arc oxidization treatment after grinding, polishing and ultrasonically cleaning the surfaces of the test pieces, putting the test pieces into silicate electrolyte, performing the micro-arc oxidization treatment for 15-20 min under the conditions that an externally applied voltage is 350-400 V, a duty ratio is 15-30% and a frequency of 400-600 Hz to finally obtain the anti-corrosion AZ91D magnesium alloy blocky material with excellent obdurability and corrosion resistance. The combined processing method for preparing the anti-corrosion AZ91D magnesium alloy with obdurability, disclosed by the invention, has the advantages of high yield, simple technological operation as well as equipment requirements and good industrial application prospect.

Description

1. Technical field [0001] The invention relates to a combined processing method for improving the structure and surface state of an AZ91D magnesium alloy by utilizing equal channel angular extrusion and subsequent micro-arc oxidation surface treatment to improve its toughness and corrosion resistance, and belongs to the technical field of alloy processing. 2. Background technology [0002] Although AZ91D magnesium alloy has good specific strength, specific stiffness and machinability, it is a hexagonal close-packed (HCP) structure with low strength and poor plasticity. In addition, magnesium alloys mainly contain magnesium. The standard electrode potential of magnesium is -2.37V, which is the most negative electrode potential among metal structural materials. At the same time, the PB ratio of the oxide film (MgO) formed on the surface of magnesium alloys in the air is <1. It cannot play a stable and effective protective effect on the matrix, so magnesium alloys are prone ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22F1/06C25D11/30
Inventor 马爱斌周祺江静华宋丹
Owner HOHAI UNIV
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