CAJ | 학술논문

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.
채용등온열처리법대ZA74미합금재부분중용과정중비지정조직적연변과정화궤리진행연구.결과표명:재중용과정중,ZA74합금원시조직중연착정계분포적Mg32(Al,Zn)49공정상축점향α-Mg기체확산용해,당온도체도공정용화후,잉여부분개시용화.비지정조직적연변시재체계자유능강저적구동하완성적,주요궤제시공정조직적고용,용질원자확산,지정조직적조화、분리、구화이급정립적합병화장대.기중,ZA74합금고상과립적분리시유용질확산、능량기복、성분기복등인소조성액상연아정계침삼화근부중용량충궤제기주도작용.
@@@@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(Al,Zn)49 eutectic phases distribute on grain boundary of ZA74 alloy initial microstructure, which gradually dissolves intoα-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 microstructure 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.