Mg-Al_4C_3中间合金在AZ91D镁合金中的细化效果及机理  

Refinement effect and mechanism of Mg-Al_4C_3 master alloy in AZ91D Mg alloy

作　　者：刘生发[1] 李波[1] 韩辉[1] 康柳根[1] 王小虎[1] 苏伟[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：《中国有色金属学报》2009年第1期32-37,共6页The Chinese Journal of Nonferrous Metals

基　　金：湖北省科技攻关资助项目(2007AA101C37))

摘　　要：采用SEM、EDS和XRD等测试手段研究粉末原位合成法制备的Mg-50%Al4C3中间合金对AZ91D镁合金显微组织的细化效果。结果表明:中间合金的加入可显著细化AZ91D镁合金的α-Mg晶粒。当Al4C3的含量为1.0%时,α-Mg晶粒的尺寸由基体合金的142.9μm降至63.2μm,降低幅度约为56%,且共晶组织形貌发生明显改变,由完全离异的骨骼状β共晶组织和共生生长层片状α+β共晶组织转变为蜂窝状的α+β部分离异共晶组织,同时β相的尺寸变小、分布更趋弥散。通过能谱分析、面错配度计算及差热分析,证实Al4C3可成为初生α-Mg晶粒的良好异质核心。此外,显微组织的细化导致合金力学性能的提高。The refinement effect of Mg-50%Al4C3 （mass fraction） master alloy on microstructures of AZ91D magnesium alloy was studied using SEM, EDS and XRD, and so on. The results show that the grain size of α-Mg in AZ91D alloy is apparently reduced after adding Mg-Al4C3 master alloy. When the content of Al4C3 is 1.0%, the average grain size of the α-Mg grain decreases from about 142.9 μm of AZ91D base alloy to 63.5μm, the reduced extent is about 56%. Meanwhile the eutectic morphologies obviously change from the fully-divorced fl eutectic and lamellar α＋β eutectic structure into honeycomb α＋β partially-divorced eutectic structure, and the size of fl phase diminishes and tends to dispersed distribution. Based on the analysis of EDS, DTA and calculation of the planar disregistry between Al4C3 and Mg, Al4C3 particles can act as the heterogeneous nucleus of primary α-Mg phase. In addition, the addition of Al4C3 improves the mechanical properties of AZ91D alloy obviously.

关 键 词：AZ91D镁合金 Mg—Al4C3中间合金 晶粒细化 力学性能 

分 类 号：TG146[一般工业技术—材料科学与工程]