Mg-16Zn-5Al合金部分重熔过程中的组织和相演变机制  

Microstructure and Phase Evolution Mechanism of Mg-16Zn-5Al Alloy During Partial Remelting

作　　者：李春[1,2] 范新会[1,2] 陈建[2] 李元东[3] 袁训锋[1] 董晓刚[1] Li Chun;Fan Xinhui;Chen Jian;Li Yuandong;Yuan Xunfeng;Dong Xiaogang(Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources,Shangluo University,Shangluo 726000,China;Xi＇an Technological University,Xi＇an 710021,China;State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]商洛学院陕西省尾矿资源综合利用重点实验室,陕西商洛726000 [2]西安工业大学,陕西西安710021 [3]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,甘肃兰州730050

出　　处：《稀有金属材料与工程》2018年第7期2072-2079,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51464031);陕西省教育厅专项科研计划资助项目(16JK1241);商洛市科技计划项目(SK2016-29)

摘　　要：研究了Mg-16Zn-5Al合金在部分重熔过程中的组织演变和相转变。结果表明:Mg-16Zn-5Al合金在440℃重熔45～60min或460℃重熔30～45 min可获得理想的半固态球晶组织,其平均晶粒尺寸为55.7～60.4μm,平均圆整度为1.18～1.29,固相率约为65%。合金在重熔过程中发生的相转变(即:MgZn+τ→α-Mg、α-Mg+MgZn+τ→L、α-Mg→L及α-Mg→L和L→α-Mg)导致了晶粒内部的快速粗化合并、组织分离、球化和后期的吞并粗化,同时晶粒内部的亚晶界和根部重熔对组织的分离起着重要作用。基于LSW理论推导出了某一保温时间段内与扩散系数相关的晶粒粗化因子M_n,用其描述晶粒在相应阶段的主要演变方式。The microstructure evolution and phase transformation of Mg-16 Zn-5 Al alloy during partial remelting were investigated. The results show that when the Mg-16 Zn-5 A1 alloy is remelted at 440 ℃ for 45～60 min or at 460 ℃ for 30～45 min,it can obtain the ideal semi-solid spherical microstructure. The average grain size is 55.7～60.4 μm, the average roundness is 1.18～1.29, and the solid fraction is about 65%. The phase transformation which includes MgZn＋τ→α-Mg, a-Mg＋MgZn＋τ→L, α-Mg→L, α-Mg→L and L→α-Mg occurs during partial remelting.They lead to the initial rapid coarsening of the grain, structure separation, spheroidization of the grain, and final merger coarsening. Meanwhile,the subboundary and root remelting within the grains play an important role in separation of the microstructure. The coarsening factor M_n which is related with diffusion coefficient of an isothermal period is deduced by LSW theory. The main evolution way of grain is described by M_n of the corresponding period.

关 键 词：Mg-16Zn-5Al合金 组织演变 相转变 部分重熔 半固态成形 

分 类 号：TG146.22[一般工业技术—材料科学与工程]