相场法模拟流动下非等温多晶粒枝晶生长形貌研究  

Research of Simulation Dendritic Growth of Polycrystalline Non-isothermal Binary Alloys by Phase Field Method

作　　者：郝丽梅[1] 

机构地区：[1]西安科技大学理学院应用物理系,西安710054

出　　处：《材料工程》2010年第6期1-6,11,共7页Journal of Materials Engineering

基　　金：西安科技大学培育基金资助课题(200847)

摘　　要：基于相场方法对包含多晶粒的非等温合金凝固过程进行了二维数值模拟。以Ni-Cu合金为例,展示了多核晶粒形貌的生长过程,研究了流速、各向异性和过冷度、晶核个数等参数对多枝晶生长形貌的影响。结果表明:随着模拟时间的增加,各晶核由独立生长演化为竞争生长;引入强制流动后,枝晶上游臂的生长得到促进,下游臂的生长受到抑制,垂直臂逐渐向迎流方向倾斜生长;随着流速的增大,多枝晶的非对称性增强,垂直臂在迎流一侧逐渐长出二次枝晶,而逆流侧保持光滑。随着各向异性值和过冷度的增大,各枝晶形貌大小均增大。Numerical simulation based on phase field method is developed to describe polycrystalline solidification of the non-isothermal binary alloy,the evolution of the interface morphology is showed and the effect of anisotropy parameter is formulated for Ni-Cu alloy.The results indicate that,with increase in time,all of nuclei grow from independence to competition.The nuclei grows into an asymmetry dendritic with a forced flow,that is,upstream dendritic arm is promoted,downstream is inhibited and tilts to down direction,and perpendicular arms have no obvious change,but tilts to upstream direction.The asymmetry of dendritic shape is intensified as the forced flow velocity is increased,where there is a secondary dendritic in the upstream direction of perpendicular arms,while there is no secondary dendritic in the downstream direction.With increase in anisotropic values or undercooling values,the size of every dendritic increase.

关 键 词：相场方法 多晶粒 非等温合金 各向异性 过冷度 

分 类 号：TG244[金属学及工艺—铸造]