SIMA法连续制备AZ91D合金半固态坯的微观组织演化  

Microstructure Evolution of AZ91D Alloy Semi-solid Billets Continuously Prepared by SIMA Method

作　　者：田文彤[1] 曹霞[1] 杨辉[1] 肖华星[1] 

机构地区：[1]常州工学院机电工程学院,江苏常州213002

出　　处：《热加工工艺》2015年第7期36-38,43,共4页Hot Working Technology

基　　金：江苏省高校自然科学基础研究项目(07KJD460007)

摘　　要：采用正挤压要等径道角挤压复合工艺对铸坯进行等效应变为4.71的预变形,并研究该预变形坯在再结晶及半固态等温处理过程中的组织演化规律。结果表明,再结晶晶粒细小、均匀,且该组织对随后的半固态等温处理过程中的组织演化及液相分布有重要影响,当在530℃保温15～30min时,所获得的晶粒平均直径为35～40μm,晶粒的形状系数为1.31～1.1,且液相的有效体积分数达到96%以上,非常适合触变成形复杂形状零部件。该工艺能为连续制备大尺寸制件奠定理论基础。Pre-deformation of casting billet with equivalent strain of 4.71 was performed by composite technology of forward extrusion-equal channel angular extrusion （FE-ECAE）. And the microstructure evolution ofpre-deformed billet in the semi-solid isothermal treatment process and recrystallization was studied. The results show that the sizes of recrystallized grains in the process are fine and uniform, which has a great influence on the subsequent microstructure evolution and the liquid phase distribution in the semi-solid isothermal treatment process. When the billet is heated at 530~C for 15-30 min, the average diameter of grains is 35-40 p,m, the shape coefficient of grains is 1.31-1.1, and the effective volume fraction of liquid phase is reached more than 96%, which is more suitable for thixo-forming complicated parts. The process can lay the theoretical foundation for the continuous preparation of large size product.

关 键 词：复合成形 组织演化 半固态等温处理 触变成形 

分 类 号：TG376.2[金属学及工艺—金属压力加工]