Ce对AZ91镁合金组织演变及力学性能的影响  

Effects of Rare Earth Ce on Microstructure and Mechanical Properties of AZ91 Magnesium Alloy

作　　者：吴安如[1] 付庆琳 艾孝文 陈娟[1] 董丽君[1] 覃波[1] Wu Anru;Fu Qinglin;Ai Xiaowen;Chen Juan;Dong Lijun;Qin Bo(Hunan Provincial Key Laboratory of Vehicle Power and Transmission System,Hunan Institute of Engineering)

机构地区：[1]湖南工程学院汽车动力与传动系统湖南省重点实验室

出　　处：《特种铸造及有色合金》2019年第3期247-251,共5页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(11572124);湖南省自然科学基金省市联合基金资助项目(2018JJ4044)

摘　　要：对AZ91镁合金进行稀土合金化设计、熔铸、塑性加工、热处理及力学性能试验,分析了稀土Ce对铸态AZ91镁合金晶粒大小、枝晶间化合物分布的影响,研究合金凝固过程中离异共晶形成及塑性变形后的组织演化及性能。结果表明,少量稀土(0.2%的Ce)能细化AZ91合金的晶粒尺寸,提高AZ91挤压板材的时效硬化速率,而Ce含量增加到0.5%后,AZ91挤压板材的时效硬化速率降低;在过时效阶段,挤压板材硬度下降是因为Ce的作用,稀土Ce对合金的过时效有较好的抑制作用。Experiment of AZ91 magnesium alloy was conducted for rare earth alloying design,molten casting,heat treatment and mechanical properties testing.Influence of Ce on grain size and interdendritic compound distribution in as-cast AZ91 magnesium alloy was analyzed.Formation of separated eutectic phase and microstructure evolution as well as properties after plastic deformation were described during solidification process.The experimental results show that trace rare earth(0.2%Ce)can fine the grain size of AZ91 alloy and improve aging hardening peak value of AZ91 extrusion sheet.Aging hardening rate of AZ91 extruded sheet is decreased with 0.5%Ce addition.In the period of overaging,the decrease of hardening-rate of the extrusion plate is slowed by the effect of the Ce,so Ce element has a good inhibitory effect on the over-aging of alloys.

关 键 词：稀土镁合金 离异共晶 塑性变形 时效硬化 过时效 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG113.25[金属学及工艺—金属材料]