挤压比对AZ91镁合金组织及力学性能的影响  

Influence of extrusion ratio on microstructures and tensile properties of AZ91 magnesium alloy

作　　者：张志远[1] 程显敏 王越[1] 张燕[1] 陈立佳[1] 刘正[1] 

机构地区：[1]沈阳工业大学材料科学与工程学院,沈阳110023 [2]大连职业技术学校,辽宁大连116023

出　　处：《沈阳工业大学学报》2006年第5期495-500,共6页Journal of Shenyang University of Technology

基　　金：辽宁省科技攻关计划资助项目(2004221009)

摘　　要：研究了挤压比对热挤压AZ91镁合金显微组织和拉伸性能的影响.结果表明:热挤压可以显著细化AZ91镁合金的晶粒,而且随着挤压比的增加,晶粒变得更加细小;增大挤压比也可以提高AZ91镁合金在不同实验温度下的抗拉强度和屈服强度,且经过3种挤压比挤压的AZ91镁合金在150℃时均呈现最高的抗拉强度和屈服强度;此外,经不同挤压比挤压的AZ91镁合金的伸长率均随实验温度的升高而增加.通过拉伸断口形貌的扫描电镜分析,确定了热挤压AZ91镁合金在室温拉伸时均表现为解理断裂为主的脆性断裂,而在较高温度下拉伸时则基本呈现韧性断裂特征.The effects of extrusion ratio on microstructures and mechanical properties of the hot-extruded AZ91 magnesium alloy had been investigated. The results reveal that the microstructure of the AZ91 alloy is effectively refined after hot-extrusion. The grains become finer with increasing extrusion ratio. The tensile strength of the extruded AZ91 alloy gets obviously enhanced with an increase in extrusion ratio. The AZ91 alloys subjected to different ratios of hot-extrusion exhibit the highest ultimate tensile and yield strengths at the test temperature of 150 ℃. The elongation to failure increases with increasing test temperature for various hot-extruded alloys. In addition, the observations on fracture surfaces had been performed by SEM, and the tensile fracture modes for the AZ91 alloy were determined. At room temperature, the tensile failure is controlled mostly by the brittle cleavage, while at high temperatures, the ductile fracture feature can be observed.

关 键 词：镁合金 热挤压 显微组织 拉伸性能 断口形貌 

分 类 号：TG146.2[一般工业技术—材料科学与工程]