Alloy solidification: Assessment and improvement of an easy-to-apply model

作     者：H.Liu Y.Liu S.L.Lu Y.Zhang H.Chen Y.Chen M.Qian H.Liu;Y.Liu;S.L.Lu;Y.Zhang;H.Chen;Y.Chen;M.Qian

作者机构：School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Centre for Additive ManufacturingSchool of EngineeringRMIT UniversityMelbourneVIC 3000Australia School of Materials Science and EngineeringSichuan UniversityChengdu 610065China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2022年第130卷第35期

页      面：1-11页

核心收录：

学科分类：07[理学] 070205[理学-凝聚态物理] 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）] 0702[理学-物理学] 

基　　金：funding from the Australian Research Council(ARC) via DP180103205。 

主　　题：Solidification Microsegregation Solute Back diffusion Eutectic formation 

摘      要：It has been a central task of solidification research to predict solute microsegregation. Apart from the Lever rule and the Scheil-Gulliver equation, which concern two extreme cases, a long list of microsegregation models has been proposed. However, the use of these models often requires essential experimental input information, e.g., the secondary dendrite arm spacing(λ), cooling rate( ˙T) or actual solidification range(△T). This requirement disables these models for alloy solidification with no measured values for λ,˙T and △T. Furthermore, not all of these required experimental data are easily obtainable. It is therefore highly desirable to have an easy-to-apply predictive model that is independent of experimental input,akin to the Lever rule or Scheil-Gulliver model. Gong, Chen, and co-workers have recently proposed such a model, referred to as the Gong-Chen model, by averaging the solid fractions(f_(s)) of the Lever rule and Scheil-Gulliver model as the actual solid fraction. We provide a systematic assessment of this model versus established solidification microsegregation models and address a latent deficiency of the model, i.e.,it allows the Lever rule solid fraction fsto be greater than one(f_(s) 1). It is shown that the Gong-Chen model can serve as a generic model for alloy solidification until fsreaches about 0.9, beyond which(f_(s) 0.9) its applicability is dictated by both the equilibrium solute partition coefcient(k) and the solute diffusion coefcient in the solid(Ds), which has been tabulated in detail.