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文章研究了电磁连铸AZ31镁合金经热挤压变形后的微观组织和力学性能。结果表明,挤压过程中的动态再结晶能够显著细化晶粒,局部细晶区的平均晶粒为2μm。与铸态合金相比,挤压后的AZ31镁合金具有更细小的晶粒和更均匀的微观组织。挤压变形后产生强烈的基面织构;挤压后材料的力学性能显著提高。屈服强度、抗拉强度和断面收缩率随着挤压比的增大而增大。挤压比为25时,屈服强度、抗拉强度和断面收缩率分别为259MPa,357MPa和30.5%,比铸态合金分别提高了86.33%,64.52%和67.40%。随着挤压比的增大,晶粒细化效果更为明显,微观组织更均匀。断口形貌分析表明,挤压变形后材料由韧脆混合型断裂,转变为韧性断裂。
The article studies the microstructure and mechanical properties of AZ31 magnesium alloy after hot extrusion deformation. The results show that the dynamic recrystallization in the extrusion process can significantly refine the grains, and the average grain size in the fine grain region is 2μm. Compared with the as-cast alloy, the extruded AZ31 magnesium alloy has finer grains and more uniform microstructure. Extruded and deformed to produce a strong basal texture; mechanical properties of the extruded material increased significantly. Yield strength, tensile strength and reduction of area increase with the extrusion ratio increases. When the extrusion ratio is 25, the yield strength, tensile strength and reduction of area are 259MPa, 357MPa and 30.5% respectively, which are respectively 86.33%, 64.52% and 67.40% higher than that of as-cast alloy. With the extrusion ratio increases, the grain refinement effect is more obvious, more uniform microstructure. The fracture surface morphology analysis shows that the material is changed from ductile-brittle fracture to ductile fracture after extrusion deformation.