铈对铸造镁合金AZ91D显微组织与力学性能的影响

Effects of Cerium on Microstructure and Mechanical Properties of As-Cast Magnesium Alloy AZ91D

利用光学金相显微镜OM和XRD分析了分别加入 0 .1%,0 .3 %,0 .5 %,0 .7%和 1.0 %Ce的AZ91D合金显微组织和相组成 ,测试了室温力学性能和硬度。结果表明 ,加入一定量Ce后的AZ91D合金形成杆状化合物Al4 Ce ,被推移到生长界面 ,阻碍枝晶的自由生长 ,从而细化合金显微组织 ;Ce能提高AZ91D合金室温抗拉强度和硬度 ,而对其屈服强度和延伸率影响不大 ;加入 0 .7%Ce的AZ91D合金晶粒细化效果好 。

Microstructures and phase compositions of AZ91D alloys after adding various Ce contents of 0 1%, 0.3%, 0.5%, 0.7% and 1.0% respectively were observed by using optical microscope and XRD, meanwhile their mechanical properties at ambient temperature and hardness were tested. The results show that a rod like compound Al4Ce is formed in AZ91D alloys after adding a certain quantity of Ce contents, which is pushed onto the growth interface and hinders the growth of the dendrite freely. Thus Ce can refine microstructures of alloys. Ce can improve tensile strength and hardness of AZ91D alloy at ambient temperature, while it has little influences on their yield strength and elongation. AZ91D alloy containing 0 7% Ce has good refinement effect and relatively ideal whole mechanical properties.