往复挤压Mg-4Al-2Si镁合金的组织细化与力学性能  

Structure refinement and mechanical properties of Mg-4Al-2Si Mg alloy by reciprocating extrusion

作　　者：宋佩维[1] 井晓天[1] 郭学锋[1] 

机构地区：[1]西安理工大学材料科学与工程学院

出　　处：《中国有色金属学报》2007年第1期111-117,共7页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(50271054);陕西省自然科学基金资助项目(2002E110);凝固技术国家重点实验室基金资助项目(200301)

摘　　要：研究往复挤压变形对Mg-4Al-2Si合金组织和性能的影响性能,探讨基体组织和Mg2Si颗粒相的细化效果与细化机制,分析Mg2Si颗粒对再结晶的影响规律。结果表明:挤压过程中发生受位错攀移控制的动态再结晶,通过晶界迁移、亚晶合并与转动机制形成细小的α(Mg)再结晶等轴晶;随着往复挤压道次的增加,动态再结晶速度加快,晶粒尺寸迅速减小;α(Mg)与Mg2Si的晶粒尺寸在铸态下分别为45和60μm,往复挤压6道次后,晶粒尺寸减小到3和1μm,形成了细小、均匀的α(Mg)等轴晶组织,Mg2Si颗粒呈细小、弥散分布;合金的力学性能随往复挤压道次的增加而显著提高。The effects of reciprocating extrusion deformation on microstructures and properties of Mg-4Al-2Si alloys were studied, and the mechanisms of grain refinement of α（Mg） and Mg2Si particles, as well as the effect of Mg2Si particles on the recrystallization were investigated. The results show that dynamic recrystallization controlled by dislocation climbing takes place during the reciprocating extrusion process. The equiaxed grains are formed by crystal boundary migration, subgrain merge and twist rotation by recrystallization. The grain size decreases and the rate of dynamic recrystallization increases with increasing passes of reciprocating extrusion. The grain sizes of as-cast α（Mg） and Mg2Si particles decrease from 45 and 60μm to 3 and 1μm after 6 passes of reciprocating extrusion, respectively. The microstructures are characterized by the fine equiaxed α（Mg） grain with homogeneous distribution of fine Mg2Si particles. The mechanical properties of alloys are improved obviously with increasing reciprocating extrusion passes.

关 键 词：Mg-4Al-2Si镁合金 往复挤压 动态再结晶 力学性能 

分 类 号：TG376.2[金属学及工艺—金属压力加工]