含Ca,Si镁合金的铸态组织及其形成机制  

AS-CAST MICROSTRUCTURE AND ITS FORMATION MECHANISM IN Mg-BASED ALLOYS CONTAINING Ca AND Si

作　　者：艾延龄[1] 罗承萍[1] 刘江文[1] 黄雁飞[1] 

机构地区：[1]华南理工大学机械工程学院,广州510641

出　　处：《金属学报》2005年第1期49-54,共6页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目50171027广东省自然科学基金重点项目013005资助~~

摘　　要：利用金相、电子显微镜、X射线衍射仪和X射线能谱仪研究了含Ca,Si镁合金的铸态组织特征.结果表明:含Si较低的合金由镁基体及CaMgSi相组成,而含Si较高的合金由镁基体及CaMgSi和Mg2Si两种相组成. CaMgSi相呈三种不同的形态:离散块状、微细点状和针状,而本身是针状的Mg2Si则以"汉字形"团块的形态存在.根据Mg-Mg2Si-CaMgSi赝三元相图,详细讨论了铸态组织的形成机制.The as-cast microstructure of Mg-based alloys containing Ca and Si was investigated using optical microscopy, XRD, SEM/EDS and TEM. It was found, that the alloy containing low Si consisted of Mg-rich matrix and CaMgSi phase, while the alloy containing higher Si consisted Of Mg2Si besides the Mg-rich matrix and CaMgSi. The phase CaMgSi existed in three different morphologies, namely discrete large angular, dispersive dot-like, and needle-like, while the Mg2Si, also needle-like, existed in the 'Chinese-script' colonies. The formation mechanism Of the as-cast microstructure was discussed in details based on a proposed pseudo-ternary Mg-Mg2Si-CaMgSi phase diagram.

关 键 词：Mg—Ca—Si合金 CaMgSi相 MG2SI相 形成机制 

分 类 号：TG113.12[金属学及工艺—物理冶金] TG146.2[金属学及工艺—金属学]