Mg-TiB_2中间合金和Sr对AZ91D镁合金显微组织的细化  

Grain Refinement of AZ91D Magnesium Alloy by Mg-TiB_2 Master Alloy and Sr

作　　者：韩辉[1] 陈阳[1] 刘生发[1] 陈欣[1] 吕程[1] 王硕黎[1] 

机构地区：[1]武汉理工大学材料科学与工程学院,武汉430070

出　　处：《材料导报》2011年第8期81-84,共4页Materials Reports

基　　金：湖北省自然科学基金(2009CDB002);武汉理工大学博士基金(471-38650510);中央高校基本科研业务费专项资金(2010-2Y-CL-029)

摘　　要：采用SEM、EDS和XRD等测试手段研究了粉末原位合成法制备的Mg-50%TiB2(质量分数,下同)中间合金的组织和结构,以及Mg-50%TiB2和Sr对AZ91D镁合金显微组织的细化效果。结果表明,1.4%(Mg-50%TiB2)中间合金和0.1%Sr的复合添加可使AZ91D镁合金的α-Mg晶粒尺寸由基体合金的240μm降至49μm。通过面错配度计算证实TiB2可成为初生-αMg的良好异质核心。加入碱土元素Sr引起合金成分过冷度增加,从而激活固/液界面前沿潜在的TiB2核心,提高TiB2的形核率。The microstructure of Mg-50%TiB2（here after in wt%） fabricated by powder in-situ synthesis process and grain refinement of AZ91D magnesium alloy with Mg-50%TiB2 and Sr were studied using SEM, EDS and XRD. It was found that combining addition of 1.4%（Mg-50%TiB2） master alloy and 0. 1%Sr to AZ91D magnesium alloy led to the α-Mg grain size decreasing from 240μm to 49μm. Based on the calculation of the planar disregistry between TiB2 and α-Mg, TiB2 particles can act as the heterogeneous nucleus of primary α-Mg phases. The addition of Sr can increase the degree of undercooling of primary α-Mg phases, and activate the potential TiB2 particles in the solid/ liquid interface.

关 键 词：AZ91D镁合金 Mg-TiB2中间合金 SR 晶粒细化 

分 类 号：TG146.22[一般工业技术—材料科学与工程]