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A kind of preparation method of yellow high-strength toughness corrosion-resistant az91 magnesium alloy bulk material

An AZ91 and magnesium alloy technology, applied in the field of preparation of yellow high-strength, toughness and corrosion-resistant AZ91 magnesium alloy bulk material, can solve the problems of large hole diameter and porosity, inability to form a complete dense film layer, poor corrosion resistance of the film layer, etc. To achieve the effect of simple process operation and equipment requirements, good industrial application prospects, and environmental friendliness

Active Publication Date: 2019-07-02
宿迁市河海大学研究院 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] Chinese patent document CN103614762A discloses a method for preparing a magnesium alloy micro-arc oxidation yellow ceramic membrane, but the ceramic membrane prepared by this method has a pore diameter of 50-100 microns, a large pore diameter and porosity, and the cross-section is full of pores. Poor, the accumulation of molten material is weak, the film layer has a strong sense of fragmentation, and a large integrated thick area cannot be formed, and the film density is poor, resulting in relatively poor corrosion resistance of the film layer
The reason is that the addition of too high a concentration of sodium aluminate enhances the conductivity of the electrolyte, greatly promotes the micro-arc oxidation reaction process, increases the discharge intensity of the film layer, and causes severe discharge in the area, and the molten metal oxide cannot be fully flowed and spread. and solidification will continue to break down, unable to form a complete dense film

Method used

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  • A kind of preparation method of yellow high-strength toughness corrosion-resistant az91 magnesium alloy bulk material
  • A kind of preparation method of yellow high-strength toughness corrosion-resistant az91 magnesium alloy bulk material
  • A kind of preparation method of yellow high-strength toughness corrosion-resistant az91 magnesium alloy bulk material

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] The as-cast Mg-9.01wt.%Al-0.71wt.%Zn alloy is processed into a 48.5mm×48.5mm×100mm block specimen with a band saw, and its surface is evenly coated with solids on the inner surface of the extrusion slider and the ECAP mold Put the lubricant into the ECAP mold and heat it to 300°C for 30 minutes with the furnace, and then apply pressure to carry out 12 consecutive passes of ECAP extrusion. After each pass of extrusion, the mold is rotated 90°, and the grains are obviously finer after 12 passes. (see figure 1 and figure 2 ). After the Mg-9.01wt.%Al-0.71wt.%Zn alloy is processed by ECAP for 12 passes, the strength and toughness are significantly improved, the room temperature tensile strength is increased by 79%, and the elongation is increased by 39% (see image 3 ). The specimen after ECAP was processed into a block sample of 26mm×22mm×6mm by wire cutting, polished and polished step by step with 400#, 800#, 1000#, 1500# sandpaper and ultrasonically cleaned in acetone...

Embodiment 2

[0033]The as-cast Mg-9.01wt.%Al-0.71wt.%Zn alloy is processed into a 48.5mm×48.5mm×100mm block specimen with a band saw, and its surface is evenly coated with solids on the inner surface of the extrusion slider and the ECAP mold Put the lubricant into the ECAP mold and heat it to 275°C for 25 minutes with the furnace, and then apply pressure for 16 consecutive ECAP extrusion passes. After each extrusion pass, the mold is rotated 90°, and the grains are refined after 16 passes. To about 5 μm, the second phase is completely broken and dispersed. After the Mg-9.01wt.%Al-0.71wt.%Zn alloy is processed by ECAP for 16 passes, the strength and toughness are significantly improved, the tensile strength at room temperature reaches 282Mpa, and the elongation reaches 17.6%, which are significantly improved compared with the as-cast sample . The specimen after ECAP was processed into a block sample of 26mm×22mm×6mm by wire cutting, polished and polished step by step with 400#, 800#, 1000#...

Embodiment 3

[0035] The as-cast Mg-9.01wt.%Al-0.71wt.%Zn alloy is processed into a 48.5mm×48.5mm×100mm block specimen with a band saw, and its surface is evenly coated with solids on the inner surface of the extrusion slider and the ECAP mold Put the lubricant into the ECAP mold and heat it to 250°C for 20 minutes with the furnace, and then apply pressure to carry out 8 consecutive ECAP extrusion passes. After each extrusion pass, the mold rotates 90°, and the grains are continuously crushed after 8 passes. Elongated and broken, and the second phase is broken and dispersed around the matrix grains. After the Mg-9.01wt.%Al-0.71wt.%Zn alloy is processed by ECAP for 8 passes, the strength and toughness are obviously improved, the tensile strength at room temperature is increased to 248Mpa, and the elongation is increased to 16.55%. The specimen after ECAP was processed into a block sample of 26mm×22mm×6mm by wire cutting, polished and polished step by step with 400#, 800#, 1000#, 1500# sandpa...

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Abstract

The invention discloses a preparation method for a yellow high-strength-and-ductility anti-corrosion AZ91 magnesium alloy block. The preparation method comprises the steps that A, an as-cast AZ91 magnesium alloy is cut into block-shaped test pieces to be subjected to continuous multi-pass equal channel angular extrusion machining, and ultra-fine grain test pieces are obtained; and B, the ultra-fine grain test pieces are cut into the needed shape, the surfaces of the test pieces are cleaned, the micro-arc oxidation reaction is conducted with the test pieces serving as anodes and stainless steel plates serving as cathodes, and according to the proportion, an electrolyte comprises 8-12 g / L sodium silicate, 6-10 g / L potassium hydroxide, 8-12 g / L potassium fluoride, 1-3 g / L staining salt potassium permanganate and sodium citrate, wherein the sodium citrate and the potassium permanganate are added according to the molar ratio of the sodium citrate to the potassium permanganate being 1:1. According to the preparation method, the sodium citrate is adopted to serve as a complex of the staining salt potassium permanganate, the stability of the potassium permanganate can be effectively improved, the film layer staining effect is promoted, the hole diameter and the porosity factor of a manufactured film layer are small, the defects such as holes and cracks do not occur, a large, thick and solid stacking area appears on the surface of the film layer, the compactness of the film layer is greatly promoted, and the anti-corrosion property is good.

Description

technical field [0001] The invention relates to a method for preparing a yellow high-strength, toughness, and corrosion-resistant AZ91 magnesium alloy bulk material, which belongs to the technical field of magnesium alloy processing. Background technique [0002] AZ91 magnesium alloy has the characteristics of low density, high specific strength, high specific stiffness and good electromagnetic shielding, and has broad application potential in aerospace, automobile, 3C electronics and other fields. However, on the one hand, due to its hexagonal close-packed structure (HCP), there are few slip systems, low strength and poor plasticity. On the other hand, the standard electrode potential of magnesium is -2.37V, and it is easy to preferentially corrode as an anode when it coexists with other metals. At the same time, the PB ratio of the oxide film (MgO) formed spontaneously in the air by magnesium alloy is <1, and the film layer is loose and porous. Can not play a stable an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25D11/30C22F1/06
CPCC22F1/06C25D11/024C25D11/026C25D11/30
Inventor 马爱斌杨晓伟刘欢江静华李玉华宋丹
Owner 宿迁市河海大学研究院