相场法模拟强各向异性作用下二元合金枝晶生长  

Phase-field simulation of dendrite growth for binary alloy with strong anisotropy

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：《中国有色金属学报》2011年第9期2216-2222,共7页The Chinese Journal of Nonferrous Metals

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

摘　　要：基于Wheeler模型和Eggleston修正强界面能各向异性的方法,建立耦合溶质场和温度场的相场模型,模拟强界面能和界面动力学各向异性下Ni-Cu合金的枝晶生长过程。结果表明:两种各向异性均显著影响枝晶生长,在强界面动力学各向异性下,固相以类矩形方式沿?110?方向生长;在强界面能各向异性及同时存在两种各向异性下,固相以枝晶方式沿?100?方向生长,界面方向不连续,枝晶臂主枝尖端出现棱角。在各向异性强度取值相同情况下,仅有界面能各向异性时,?100?方向枝晶尖端温度梯度大,生长迅速,稳态生长速度比同时存在两种各向异性的大32.26%;仅有界面动力学各向异性时,?100?方向枝晶尖端温度梯度小且溶质浓度高,生长缓慢,稳态生长速度比同时存在两种各向异性的小48.92%。Based on the Wheeler model and the Eggleston regularization technique of strong anisotropy of interface energy,the phase-field model was built by coupling with the concentration field and temperature field.The dendrite growth process of Ni-Cu alloy with strong surface energy and kinetic anisotropy were simulated.The results show that the dendrite growth depends on the two kinds of anisotropies.Under the strong surface kinetic anisotropy condition,the melt solidifies grow along the -110- orientation and the crystals grow into a square-like.Under the strong surface energy anisotropy or having two kinds of anisotropies condition,the melt solidifies in a dendrite pattern grow along the -100- orientation and the variation of interface orientation discontinuity can lead to the corners form on the tip of dendrite.In the case of anisotropy strength with the same values,under the strong surface energy anisotropy condition,the thermal gradient along the -100- orientation is large,and makes the dendrite growth become fast,the tip velocity at steady state increases by about 32.26% compared with the case that having two kinds of anisotropies.Under the strong surface kinetic anisotropy condition,the thermal gradient along the -100- orientation is small and the concentration of solute is large,and makes the dendrite growth become slow,the tip velocity at steady state decreases by about 48.92% compared with the case that having two kinds of anisotropies.

关 键 词：二元合金 界面能各向异性 界面动力学各向异性 相场法 枝晶生长 

分 类 号：TG146[一般工业技术—材料科学与工程]