混合稀土及半固态等温热处理对原位Mg_2Si/Al复合材料组织与性能的影响  

Effect of Mischmetal and Semi-Solid Isothermal Heat Treatment on Microstructure and Properties of In Situ Mg_2Si/Al Composites

作　　者：林继兴[1,2] 童先[1] 洪威[1] 牛丽媛[1] 李光玉[2] 赵岚[1] 

机构地区：[1]浙江工贸职业技术学院材料工程系,浙江温州325003 [2]吉林大学材料科学与工程学院,吉林长春130012

出　　处：《铸造》2014年第6期587-590,共4页Foundry

基　　金：温州市重点创新团队项目(C20120003);浙江省新苗人才计划项目(2012R444003)

摘　　要：在原位Mg2Si/Al复合材料中,通过混合稀土变质及半固态等温热处理,分析变质及等温热处理后材料组织与力学性能的变化。结果表明:添加0.8%的混合稀土对Mg2Si起到很好的变质效果,初生Mg2Si的形貌由变质前的粗大十字状变为均匀分布的不规则块状,平均尺寸由变质前的74μm减小至24μm左右;同时,材料的力学性能也显著提升,抗拉强度由变质前的134 MPa提高至187.5 MPa,布氏硬度由HB 74.5提升至HB 89.5左右。最佳的等温热处理工艺为600℃保温90 min,此时,材料中初生Mg2Si转变为近球形,其形状因子为0.93左右,平均尺寸29μm左右。The microstructure and mechanical properties of in situ Mg2Si/Al composites after mischmetal（RE） modification and semi-solid isothermal heat treatment were investigated.The results show that 0.8wt% addition of RE has a good effect on Mg2Si/Al composites.The morphology of primary Mg2Si became irregular blocks distributed uniformly rather than coarse and crossed before.The average size decreased from 74 μm to about 24 μ m.Meanwhile,the mechanical properties also improved and the tensile strength increased from 134 MPa before modification to 187.5 MPa.The Brinell hardness increased from HB74.5 to about HB 89.5.The optimum isothermal heat treatment process is to keep 600 ℃ for 90 min,which could turn the shape of the primary Mg2Si into sphere.Its shape factor is about 0.93 and the average size is around 29 Lμm.

关 键 词：原位Mg2Si AL复合材料 混合稀土变质 半固态等温热处理 

分 类 号：TB333[一般工业技术—材料科学与工程]