Entropy as a selection rule for crystal growth in undercooled binary eutectic melts  

作　　者：LU YiPing XI ZengZhe YANG GenCang LIN Xin ZHOU YaoHe 

机构地区：[1]State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China [2]School of Materials and Chemical Engineering, Xi'an Technological University, Xi'an 710032, China

出　　处：《Chinese Science Bulletin》2009年第6期1012-1018,共7页

基　　金：Supported by the National Natural Science Foundation of China (Grant No. 50395103);Doctorate Foundation of Northwestern Polytechnical University (Grant No. CX200506)

摘　　要：A solution entropy model was developed for the undercooled binary eutectic alloy systems. As an ex-tension of Taylor and Fidler et al.'s model, the present model considered the change of phase compo-sition with the increase of undercooling. Furthermore, the sub-regular solution model and the interac-tion parameter (IAB) were also introduced. In this paper, the extended model is used to calculate the solution entropy for binary eutectic phases under the undercooled condition, and the application scope of the model is also extended. Not only the growth manner of eutectic phases, but also the transition of morphologies may be predicted and explained by calculating the solution entropy of eutectic phases under the non-equilibrium condition with the developed model. Experimental results show that the developed model is valid for the undercooled Ni-Si and Ni-Sn eutectic alloy systems.A solution entropy model was developed for the undercooled binary eutectic alloy systems. As an extension of Taylor and Fidler et al.＇s model, the present model considered the change of phase composition with the increase of undercooling. Furthermore, the sub-regular solution model and the interaction parameter （IAB） were also introduced.. In this paper, the extended model is used to calculate the solution entropy for binary eutectic phases under the undercooled condition, and the application scope of the model is also extended. Not only the growth manner of eutectic phases, but also the transition of morphologies may be predicted and explained by calculating the solution entropy of eutectic phases under the non-equilibrium condition with the developed model. Experimental results show that the developed model is valid for the undercooled Ni-Si and Ni-Sn eutectic alloy systems.

关 键 词：熵模型 共晶相 二元 晶体生长 选择规则 熔体 相互作用参数 正规溶液模型 

分 类 号：O781[理学—晶体学] TP391.4[自动化与计算机技术—计算机应用技术]