Phase-field-lattice Boltzmann simulation of dendrite growth under natural convection in multicomponent superalloy solidification

作     者：Cong Yang Qing-Yan Xu Bai-Cheng Liu Cong Yang;Qing-Yan Xu;Bai-Cheng Liu

作者机构：Key Laboratory for Advanced Materials Processing Technology(Ministry of Education)School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2020年第39卷第2期

页      面：147-155页

核心收录：

学科分类：08[工学] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0702[理学-物理学] 

基　　金：financially supported by the National Key Research and Development Program of China(No.2017YFB0701503) the National Science and Technology Major Project(No.2017ZX04014001) the National Natural Science Foundation of China(No.51374137). 

主　　题：Dendrite growth Natural convection Phasefield model Lattice Boltzmann method 

摘      要：The thermosolutal convection can alter segregation pattern,change dendrite morphology and even cause freckles formation in alloy solidification.In this work,the multiphase-field model was coupled with lattice Boltzmann method to simulate the dendrite growth under melt convection in superalloy solidification.In the isothermal solidification simulations,zero and normal gravitational accelerations were applied to investigate the effects of gravity on the dendrite morphology and the magnitude of melt flow.The solute distribution of each alloy component along with the dendrite tip velocity during solidification was obtained,and the natural convection has been confirmed to affect the microsegregation pattern and the dendrite growth velocity.In the directional solidification simulations,two typical temperature gradients were applied,and the dendrite morphology and fluid velocity in the mushy zone during solidification were analyzed.It is found that the freckles will form when the average fluid velocity in the mushy zone exceeds the withdraw velocity.