连铸AZ31镁合金的热挤压变形组织与性能(英文)  

Microstructure and mechanical properties of as-extruded continuous casting AZ31 magnesium alloy

作　　者：陈国清[1] 宋军辉[1] 付雪松[1] 胥广亮[1] 周文龙[1] 

机构地区：[1]大连理工大学材料科学与工程学院,大连116085

出　　处：《塑性工程学报》2009年第6期50-55,共6页Journal of Plasticity Engineering

摘　　要：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。This paper has studied the microstructure and the mechanical properties of hot extruded AZ31 alloy. The experiment results demonstrate that the extrusion processing gives rise to a strong basal texture. The grains are significantly refined and the average grain size of the localized fine grain area is 2μm due to the dynamic recrystallization during the extrusion. Compared with the EMC ingots, as-extruded specimens have much finer grain size and more uniform mierostructure. The mechanical properties of the deformed AZ31 are improved after hot-extrusion. The yield strength, ultimate tensile strength and the reduction in crosssectional area increase obviously with the increasing of extrusion ratio. When the extrusion ratio is 25, the yield strength, ultimate tensile strength and the reduction in cross-sectional area of as-extruded AZ31 alloy are 259MPa, 357MPa and 30.5%, which are enhanced by 86.33%, 64. 52% and 67.40% respectively, compared with those of as-cast samples. , The significance of the grain refining effect and the uniformity of the microstructure increase with the increase of extrusion ratio. The observation on the fracture surfaces demonstrates that the fracture mode changes from ductile-brittle fracture to ductile fracture after extrusion.

关 键 词：AZ31镁合金 电磁连铸 热挤压 力学性能 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG376.2[金属学及工艺—金属材料]