强制对流作用下多晶粒生长的相场模拟  

Phase Field Method of Multiple Grains Growth in Forced Flow

作　　者：袁训锋[1] 丁雨田[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：《材料导报》2011年第4期115-118,122,共5页Materials Reports

基　　金：兰州市科技局基金(2009-1-9);兰州理工大学博士基金(SB01200606)

摘　　要：采用Tong和Beckermann等提出的耦合流场相场模型对纯镍凝固中多晶粒枝晶的生长过程进行模拟,研究了多晶粒枝晶的生长形貌和温度分布。结果表明,熔体流动显著改变凝固前沿的传热,从而影响枝晶生长。受熔体流动和多晶粒之间相互影响的共同作用,枝晶在4个最优生长方向上的形貌呈现不对称;熔体流动还改变了枝晶的水平最优生长方向,使得水平主枝向上游倾斜;此外,二次枝晶出现径向熔化和轴向熔化等粗化方式。The phase-field model based on the Tong and Beckermann model coupled with the flow field was used to simulate mierostructural dendrite growth of multiple grains for pure metal. The morphologies of dendrites and distribution of temperature was studied. The results show that fluid flow alters the local heat transfer at the solidification front, thus the growth of the dendrite is affected. Due to the flow and the effect between muhiple grains, the dendrites present asymmetric morphologies in four preferred directions. Another effect of the flow is that the horizontal preferred directions is changed, hence horizontal main stem tilts towards the upstream direction. As the computation proceeds, secondary arms become coarsened apparently through two different modes.

关 键 词：相场法 强制对流 多晶粒 凝固 

分 类 号：TG248[金属学及工艺—铸造]