Microstructural evolution of equal channel angular pressed AZ91D magnesium alloy during semi-solid isothermal heat treatment  

作　　者：Chen Tijun Lu Guoxiang Hao Yuan 

机构地区：[1]State Key Lab of Gansu New Non-ferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050, Gansu, China

出　　处：《China Foundry》2008年第4期234-239,共6页中国铸造（英文版）

基　　金：supported by the National Basic Research Program of China(grant No.G2007CB613706);the Development Program for Outstanding Young Teachers in Lanzhou University of Technology;the Opening Foundation of State Key Laboratory of Advanced Non-ferrous Materials.

摘　　要：The microstructural evolution of AZ91D magnesium alloy processed by equal channel angular pressing during isothermal heat treatment at 570℃was investigated.The results indicated that the equal channel angular pressing followed by semi-solid isothermal heat treatment was an effective method to prepare semi-solid nondendritic slurry of AZ91D magnesium alloy.During this process,its microstructure change underwent four stages,the initial coarsening stage,the structure separation stage,the spheroidization stage and the final coarsening stage.The microstructural spheroidization effect was the best after being heated for 15 min for the alloy pressed for four passes,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 kept constant,the grain size and shape factor decreased with the increase of pressing passes.The microstructural evolution of AZ91D magnesium alloy processed by equal channel angular pressing during isothermal heat treatment at 570℃ was investigated. The results indicated that the equal channel angular pressing followed by semi-solid isothermal heat treatment was an effective method to prepare semisolid nondendritic slurry of AZ91D magnesium alloy. During this process, its microstructure change underwent four stages, the initial coarsening stage, the structure separation stage, the spheroidization stage and the final coarsening stage. The microstructural spheroidization effect was the best after being heated for 15 min for the alloy pressed for four passes, 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 kept constant, the grain size and shape factor decreased with the increase of pressing passes.

关 键 词：AZ91D magnesium alloy semi-solid isothermal heat treatment MICROSTRUCTURE semi-solid forming 

分 类 号：TU51[建筑科学—建筑技术科学] TG146.22[一般工业技术—材料科学与工程]