AZ91D镁合金流变压铸成形组织特征  

Microstructural characteristics of the rheo-diecasting AZ91D magnesium alloy

作　　者：杨柳青[1,2] 康永林[1] 张帆[1] 丁瑞华[1] 李炯 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]北京有色金属研究总院,北京100088 [3]北京广灵精华科技有限公司,北京102211

出　　处：《北京科技大学学报》2010年第6期770-776,共7页Journal of University of Science and Technology Beijing

基　　金：国家重点基础研究发展计划资助项目(No.2006CB605203);国家高技术研究发展计划资助项目(No.2006AA03Z115);"十一五"国家科技支撑计划资助项目(No.2006BAE04B09-4)

摘　　要：以AZ91D镁合金建筑刮板为例,将自行开发的锥桶式流变成形机(TBR)与TOYOBD-900V4-T冷室压铸机相结合实现了流变压铸成形工艺过程.研究了不同流变成形工艺下压铸件的组织特征,分析了成形过程中浆料的组织形成机理及凝固行为.结果表明:该流变成形工艺可以获得内部组织细小、初生α-Mg晶粒呈近球形或球形且分布均匀的成形件.当内锥桶转速为700r.min-1时,压铸件内部组织较圆整、均匀,平均晶粒尺寸约45μm,形状因子约0.81.流变压铸过程中合金熔体的凝固主要经历了一次凝固和二次凝固两个阶段.Take an AZ91D alloy architectural scraper for example,the rheo-diecasting process was implemented by combining a self-developed taper barrel rheomoulding （TBR） machine with a TOYO BD-900V4-T cold chamber die-casting machine.The microstructural characteristics of the components were investigated in different rheo-diecasting processes,and the microstructure formation and solidification behavior of the semi-solid slurry were analyzed.The results show that the process is able to obtain components in which the primary α-Mg particles are fine,spherical or nearly spherical and uniformly distributed.The microstructure of rheo-diecasting components is relatively round and homogeneous when the rotation speed is 700r·min-1.The primary α-Mg particles have an average size of about 45 μm and a shape factor of about 0.81.Solidification of the alloy melt taking place in the rheo-diecasting process is composed of two distinct stages：primary solidification and secondary solidification.

关 键 词：AZ91D镁合金 流变压铸 微观组织 组织演变 凝固行为 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG249.2[金属学及工艺—金属材料]