等通道转角挤压AZ91D镁合金在半固态等温热处理过程中的组织演变  

Microstructure Evolution of AZ91D Magnesium Alloy by Equal Channel Angular Pressing During Semi-Solid Isothermal Heat Treatment

作　　者：路国祥[1] 陈体军[1] 郝远[1] 

机构地区：[1]兰州理工大学,甘肃省有色金属新材料省部共建国家重点实验室,甘肃兰州730050

出　　处：《铸造》2008年第6期544-548,共5页Foundry

基　　金：国家973计划资助项目(2007CB613706)

摘　　要：用金相显微镜观察了等通道转角挤压AZ91D镁合金在570℃等温热处理过程中的组织演变。结果表明,等通道转角挤压后半固态等温热处理是一种适于制备AZ91D镁合金半固态浆料的方法。该材料的微观组织在此过程中经历了四个阶段:初期的快速粗化阶段、组织分离阶段、晶粒球状化阶段和最后的粗化阶段。当挤压4道次后,加热时间为15 min时,组织球化效果最好,晶粒最细小;而后随着加热时间的延长,晶粒尺寸和形状系数逐渐增大;当加热时间一定时,随着挤压道次的增加,组织的晶粒尺寸和形状系数减小。The metalloscope was used to observe the microstructure evolution of AZ91D magnesium alloy by equal channel angular pressing during isothermal heat treatment at 570 ℃. The results indicated that semi-solid isothermal heat treatment after equal channel angular pressing was a kind of effective method of preparing the semi-solid slurry of AZ91D magnesium alloy. During this process, its microstructure experienced four stages： the initial coarsening stage, microstructure separation stage, spheroidization stage and the final coarsening stage. The spheroidization effect of microstructure was the best after being pressed for four passes and heating for 15 min, and the grain size was the smallest. With the further increase of heating time, the grain size and shape factor increased. When the heating time was constant, the grain size and shape factor decreased with the increase of pressing passes.

关 键 词：AZ91D镁合金 半固态等温热处理 组织 半固态成形 

分 类 号：TG376[金属学及工艺—金属压力加工]