A Cryogenic Magnetic Field Treatment Method for Improving Plastic Workability of Magnesium Alloys

Abstract

The invention provides a cryogenic magnetic field treatment method for improving the plastic processing performance of magnesium alloys, that is, the magnesium alloy sample is lowered to an ultra-low temperature with liquid nitrogen according to a certain cooling rate, and then subjected to magnetic field treatment at a constant low temperature, and then kept at a constant low temperature for a certain period of time. Then, return to room temperature with a certain heating rate and then heat up to the tempering temperature, and then cool to room temperature with the furnace after the tempering holding time is up; Under the coupling effect of cold and magnetic field, the basal texture of magnesium alloy is weakened to improve the plastic processing performance of magnesium alloy at room temperature, which has the advantages of low investment and significant effect.

Description

technical field [0001] The invention relates to a method for improving the plastic processing performance of a magnesium alloy, in particular to a cryogenic magnetic field treatment method for improving the plastic processing performance of a magnesium alloy, and belongs to the technical field of new material processing and preparation. Background technique [0002] Magnesium and magnesium alloys have become one of the lightest metals in the application of engineering structural materials due to their good comprehensive properties. They have low density, high specific strength, specific stiffness, and elastic modulus. They are thermally conductive, electrically conductive, and damping. And electromagnetic shielding performance is superior, widely used in industrial production. [0003] Since the crystal structure of magnesium alloy is mainly hexagonal close-packed, the most common slip systems are a / 3<11-20> Burgers vector basal slip system ({0001}<11-20>) and cy...

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Problems solved by technology

[0003] Since the crystal structure of magnesium alloy is mainly hexagonal close-packed, the most common slip systems are a / 3 Burgers vector basal slip system ({0001}) and cylindrical slip system ({1-100}), the basal slip provides 3 geometric slip systems, of which there are only 2 independent slip modes; the cylindrical slip system is difficult to start at room temperature, so the magnesium alloy The plasticity, processability and formability at medium, low temperature and room temperature are very poor, which seriously limits its application range

[0004] Therefore, people have done a lot of work on improving the room temperature plasticity of magnesium alloys. These works are mainly to obtain magnesium alloy deformed materials with weak base surface texture by adding alloy elements and changing processing methods to improve their room temperature plasticity. The application number is The patent of CN200810058278.9 provides a method for preparing a magnesium alloy plate with high room temperature plasticity by hot extrusion processing. The magnesium alloy plate is prepared by hot extrusion with an extrusion die with a special shape of the die hole. The symmetrical structure of the die hole can generate shear stress during the hot extrusion process of the magnesium alloy sheet, which is beneficial to the shear plastic deformation of the magnesium alloy during the hot extrusion process, so that the magnesium alloy sheet after hot extrusion has a lower strength { 0002} basal surface texture, thereby improving the room temperature plasticity of the magnesium alloy sheet. The patent application number CN200910011111.1 aims at the shortcomings of the current magnesium alloy sheet, such as poor room temperature plasticity, large anisotropy, and low strain hardening index, provides Composition of a novel magnesium alloy with weak basal texture and low anisotropy with room-temperature formability and its hot-rolling process for sheet preparation, which produces Mg-Zn-RE magnesium alloy sheets with weak basal texture , high strain hardening exponent and low anisotropy factor, elongation at room temperature is 30-45%, of which 30-40% and 35-46% in the transverse direction and longitudinal direction, respectively, the weak basal texture obtained by these methods Although the magnesium alloy deformed material has high room temperature plasticity, its strength is very low, the yield strength is 180MPa, tensile strength>260MPa), which greatly reduces the competitiveness of this magnesium alloy deformed material with weak base texture, and limits its wide application

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