A method for refining the microstructure of hot-extruded magnesium alloy

A magnesium alloy and hot extrusion technology, applied in the field of extruded magnesium alloy, can solve the problems of dynamic recrystallization and growth, affecting the mechanical properties of extruded alloys, etc.

Active Publication Date: 2019-09-13
CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The hot extrusion deformation method can significantly refine the microstructure of magnesium alloys through dynamic recovery and dynamic recrystallization, but due to the preheating before extrusion, friction heat and deformation heat during extrusion, the extrusion after extrusion The temperature of the material is very high, which will cause the dynamic recrystallization to grow and seriously affect the mechanical properties of the extruded alloy.

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  • A method for refining the microstructure of hot-extruded magnesium alloy
  • A method for refining the microstructure of hot-extruded magnesium alloy
  • A method for refining the microstructure of hot-extruded magnesium alloy

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preparation example Construction

[0071] The present invention has no special limitation on the preparation method of the hot-extruded magnesium alloy, which can be prepared by methods well known to those skilled in the art. In the present invention, the preparation method of the hot extruded magnesium alloy is preferably:

[0072] The deformed magnesium alloy is extruded by a magnesium profile extruder to obtain a hot extruded magnesium alloy.

[0073] In the present invention, the composition of the deformed magnesium alloy is consistent with the composition of the above-mentioned hot extruded magnesium alloy, and the composition is:

[0074] 8-9wt% Al;

[0075] 0.4-0.8wt% Zn;

[0076] 0.8-1.4wt% La;

[0077] 0.1-0.3wt% Mn;

[0078] The balance is Mg and unavoidable impurities.

[0079] The present invention has no special limitation on the preparation method of the wrought magnesium alloy, which can be prepared by using the wrought magnesium alloy preparation method well known to those skilled in the a...

Embodiment 1

[0102] Mixing high-purity magnesium, high-purity aluminum, high-purity zinc, magnesium-lanthanum master alloy containing 20% ​​lanthanum and aluminum-manganese master alloy containing 10% manganese;

[0103] Add high-purity magnesium into an iron crucible preheated at 250°C, and add No. 5 flux to cover;

[0104] After the high-purity magnesium is completely melted, the temperature of the melt is raised to 740°C, and high-purity aluminum, high-purity zinc, magnesium-lanthanum master alloy containing 20% ​​lanthanum and 10% manganese are added to the melt in batches. Aluminum-manganese master alloy, keep the melt temperature at 720-780°C during this process;

[0105] After all the additions are completed, stir for 20 minutes, refine with argon gas, and then stand still for 40 minutes to cast a magnesium alloy ingot by semi-continuous casting, which is a deformed magnesium alloy. The volume ratio of the runner and the crystallizer is 100:1. CO 2 and SF 6 Mixed gas as shielding...

Embodiment 2

[0108] Heat the deformed magnesium alloy prepared in Example 1 at 380°C for 2 hours, then heat it at 410°C for 14 hours for solution treatment, quench and cool the magnesium alloy after solution treatment, and turn the cooled magnesium alloy to a length of Ф82mm 120mm.

[0109] Preheat the turned magnesium alloy in a preheating furnace at 250°C for 2.5 hours, and then extrude it into a round bar with a 630-ton magnesium profile extruder at a temperature of 250°C and an extrusion speed of 0.5mm / s. The extrusion ratio is 18:1 to obtain hot extruded magnesium alloy.

[0110] The hot-extruded magnesium alloy obtained at the extrusion outlet is cooled with liquid nitrogen by the above-mentioned cooling device, and the flow rate of the liquid nitrogen is controlled to be 1.2m 3 / h, to obtain a hot extruded magnesium alloy with fine grains.

[0111] Observing the microstructure of the hot-extruded magnesium alloy with fine grains obtained in Example 2 of the present invention, the ...

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Abstract

The invention provides a method for refining the microstructure of a hot-extruded magnesium alloy, comprising: cooling the hot-extruded magnesium alloy by applying liquid nitrogen to the hot-extruded magnesium alloy; the cooling device includes: a bracket ( 10); be fixed on the support (10) and be used for storing the liquid nitrogen storage tank (4) of liquid nitrogen; Support (10) is the inverted U-shaped baffle that covers on the workpiece (8), the inverted U-shaped baffle The top surface and two side surfaces have a baffle structure; a nozzle (7) arranged at the outlet of the liquid nitrogen storage tank (4), the nozzle (7) is used to spray liquid nitrogen onto the workpiece (8); A valve (6) arranged between the liquid nitrogen storage tank (4) and the nozzle (7); the flow rate of liquid nitrogen in the cooling process is 0.6-1.2m 3 / h. The invention adopts a specific cooling device and controls the flow rate of liquid nitrogen to avoid the risk of liquid nitrogen splashing and profile bursting, and the microstructure of the hot-extruded magnesium alloy is obviously refined.

Description

technical field [0001] The invention relates to the technical field of extruded magnesium alloys, in particular to a method for refining the microstructure of hot extruded magnesium alloys. Background technique [0002] Magnesium and its alloys have a very small specific gravity (the specific gravity of pure magnesium is 1.74g / cm 3 ), compared to aluminum (2.70g / cm 3 ) and iron (7.80g / cm 3 ) are 35.6% and 77.7% smaller, respectively, and are the lightest among currently available metallic materials. At the same time, magnesium and its alloys also have the advantages of high specific strength, high specific stiffness, good damping performance, good electromagnetic shielding, and good machinability, and have good application prospects in the field of weight reduction of structural materials. [0003] At present, magnesium alloys still have the problem of low mechanical properties, which affects the large-scale application of magnesium alloys. In order to improve the mechan...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22F1/06C22C23/02
Inventor 孟健邱鑫孙伟杨强管凯田政张德平牛晓东刘孝娟
Owner CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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