镁合金中混合稀土加入方法研究  

Investigation on Joined Technique of Mischmetal in Magnesium Alloy

作　　者：徐玉磊[1] 张奎[1] 李兴刚[1] 袁海波[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,北京100088 [2]东风汽车有限公司商用车技术中心工艺研究所,湖北十堰442001

出　　处：《热加工工艺》2009年第5期1-4,7,共5页Hot Working Technology

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

摘　　要：研究在镁合金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:在实验室中采用井式坩埚炉,在熔炼温度达到720℃时,直接添加混合稀土,30min内收得率低于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,金相分析及TG-DSC分析表明形成种类较多、晶粒细小的低熔点的Mg-RE金属间化合物。采用井式坩埚炉,在熔炼温度达到720℃时,以铸态中间合金向重力铸造镁合金添加混合稀土时容易形成枝晶组织,而且收得率低于以挤压态中间合金添加混合稀土的收得率。在常规冷室压铸条件下,以铸态中间合金方式添加混合稀土与以挤压态中间合金方式添加混合稀土相比,虽然收得率仍较低,但是组织区别不明显。The joined technique of dollop-like mischmetal, as-cast and extruded Mg-mischmetal master alloy in magnesium alloy AZ91D was investigated. The results showed that the absorptivity of mischmetal achieved less than 50% within 30 minutes when mischmetal was added by dollop-like at 720 ℃. The Mg-MM master alloy was prepared by permanent mould casting and then was extruded into the bars. The microstructure and analytical studies were carried out using optical microscopy, SEM and differential scanning calorimetry （DSC）. Testing results showed that the Mg-MM master alloy could melt easily at 720 ℃, RE containing Mg phase with lower melting point was formed. The absorptivity of mischmetal added by as-cast Mg-MM master alloy was lower than that added by extruded Mg-MM master alloy. The dendritic structures were observed when mischmetal was added by as-cast Mg-MM master alloy. Then magnesium alloy test bars were produced under conventional cold chamber die casting condition with addition of as-cast and extruded Mg-MM master alloy. The absorptivity of mischmetal added by as-cast Mg-MM master alloy was still lower that added by extruded Mg-MM master alloy,but there wasn＇t obvious difference between microstructures of die-casting magnesium added mischmetal by different way.

关 键 词：镁合金 富铈稀土 加入方法 收得率 混合稀土 

分 类 号：TG249.2[金属学及工艺—铸造]