Effect of nonlinear liquidus and solidus on dendrite growth in bulk undercooled melts  

作　　者：陈正 王海丰 刘峰 杨伟 

机构地区：[1]State Key Laboratory of Solidification Processing,North western Polytechnical University

出　　处：《Transactions of Nonferrous Metals Society of China》2010年第3期490-494,共5页中国有色金属学报（英文版）

基　　金：Projects(50501020, 50395103, 50431030) supported by the National Natural Science Foundation of China;Project(NCET-05-870) supported by Program for New Century Excellent Talents in Chinese University;Project(CX200706) supported by the Doctorate Foundation of Northwestern Polytechnical University,China

摘　　要：On the base of nonlinear liquidus and solidus,an extended model for dendrite growth in bulk undercooled melts was developed under local non-equilibrium conditions both at the interface and in the bulk liquid.In terms of thermodynamic calculations of the phase diagram,the model predictions are relatively realistic physically,since few fitting parameters are used in the model predictions.Adopting three characteristic velocities,i.e.the critical velocity of absolute solute stability(VC*),the velocity of maximal tip radius(VRm),and the velocity of bulk liquid diffusion(VD),a quantitative agreement is obtained between the model predictions and the experimental results in undercooled Ni-0.7%B and Ni-1%Zr(molar fraction) alloys,and the overall solidification process can be categorized.On the base of nonlinear liquidus and solidus,an extended model for dendrite growth in bulk undercooled melts was developed under local non-equilibrium conditions both at the interface and in the bulk liquid.In terms of thermodynamic calculations of the phase diagram,the model predictions are relatively realistic physically,since few fitting parameters are used in the model predictions.Adopting three characteristic velocities,i.e.the critical velocity of absolute solute stability（VC＊）,the velocity of maximal tip radius（VRm）,and the velocity of bulk liquid diffusion（VD）,a quantitative agreement is obtained between the model predictions and the experimental results in undercooled Ni-0.7%B and Ni-1%Zr（molar fraction） alloys,and the overall solidification process can be categorized.

关 键 词：dendrite growth undercooled melts Ni-based alloys 

分 类 号：TG111.7[金属学及工艺—物理冶金]