压铸镁合金中混合稀土加入方法研究  

Added Ways of Mistchmetal (MM) in Die-casting Magnesium Alloy

作　　者：徐玉磊[1] 张奎[1] 李兴刚[1] 雷健[2] 

机构地区：[1]北京有色金属研究总院有色金属制备加工国家重点实验室 [2]东风汽车有限公司商用车技术中心工艺研究所

出　　处：《特种铸造及有色合金》2009年第2期123-126,共4页Special Casting & Nonferrous Alloys

基　　金：国家“十一五”科技支撑计划资助项目(2006BAE04B01,2006BAE04B04)

摘　　要：研究了在压铸镁合金AZ91D中直接添加和以中间合金方式添加混合稀土的优缺点。结果表明,直接添加混合稀土时,用井式坩埚炉在熔炼温度为720℃时,60min内混和稀土收得率低于50%。采用先铸造后挤压的方式制备了镁基混合稀土中间合金,金相分析表明形成种类较多、晶粒细小的Mg-RE金属间化合物,差热分析显示其中一些金属间化合物的熔点低于压铸温度,溶解速度较快。用井式坩埚炉在熔炼温度为720℃时,10min内,以铸态和挤压态中间合金添加混合稀土时,混和稀土收得率分别为94%和96%。在常规冷室压铸条件下,以挤压态中间合金方式在压铸镁合金AZ91D中添加混合稀土收得率达到80%,稀土元素能被合金化。Effects of added ways,such as direct addition and master alloy addition,on absorptivity of MM in die casting magnesium alloy were investigated.The results indicate that mistchmetal absorptivity is less than 50% by directly adding mistchmetal with melting at 720℃ in well type crucible furnace for less than 30 min.Mg matrix mischmetal can be prepared by casting combining with squeezing casting method,which exhibits Mg-RE metallic compound with various types and fine grain sizes from OM(optical microscope)analysis,and melting point is higher than die casting temperature from DSC observation,leading to fast solution velocity.The mistchmetal absorptivity can reach 94% and 96%,respectively,with adding mischmetal in as-cast ways and in extruded ways at 720℃ within 10 min in well type crucible furnace.Mischmetal absorptivity can reach up to 80% in die casting AZ91D magnesium in conventional cold chamber die casting machine with adding extruded master alloy,showing acceptable alloying process for RE element.

关 键 词：镁合金 稀土 压铸 加入方法 

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