ZA74镁合金非枝晶组织的演变过程及机理  

Non-dendritic microstructure evolution process and mechanism of ZA74 magnesium alloy

作　　者：冯凯[1] 黄晓锋[1] 马颖[1] 阎峰云[1] 郝远[1] 

机构地区：[1]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,兰州730050

出　　处：《中国有色金属学报》2013年第3期635-644,共10页The Chinese Journal of Nonferrous Metals

基　　金：国家重点基础研究发展计划前期研究专项(2010CB635106);甘肃省高等学校基本科研项目

摘　　要：采用等温热处理法对ZA74镁合金在部分重熔过程中非枝晶组织的演变过程和机理进行研究。结果表明:在重熔过程中,ZA74合金原始组织中沿着晶界分布的Mg32(Al,Zn)49共晶相逐渐向α-Mg基体扩散溶解,当温度达到共晶熔化后,剩余部分开始熔化。非枝晶组织的演变是在体系自由能降低的驱动下完成的,主要机制是共晶组织的固溶,溶质原子扩散,枝晶组织的粗化、分离、球化以及晶粒的合并和长大。其中,ZA74合金固相颗粒的分离是由溶质扩散、能量起伏、成分起伏等因素造成液相沿亚晶界浸渗和根部重熔两种机制起主导作用。The non-dendritic microstructure evolution process and mechanism analysis of ZA74 magnesium alloy during partial remelting were investigated by isothermal heat-treatment. The results indicate that the Mg32（A1,Zn）49 eutectic phases distribute on grain boundary of ZA74 alloy initial mierostructure, which gradually dissolves into a-Mg matrix due to the diffusion of the solute and the remainder is melted when the temperature reaches up to eutectic melted. The evolution of non-dendritic microstructure is driven by the free energy reduction. The main mechanisms are the eutectic microstmcture solution, solute diffusion, coarsening, dendrite separation, spheroidization and final coarsening during partial remelting. Furthermore, the appearance of subboundary and root remelting results from the solute diffusion, energy fluctuation and constituent fluctuation which are the separation mechanisms of ZA74 particle during partial remelting.

关 键 词：ZA74镁合金 部分重熔 半固态 非枝晶组织 演变机理 

分 类 号：TG146.22[一般工业技术—材料科学与工程]