A thermodynamic extremal principle incorporating the constraints from both fluxes and forces.Ⅱ.Application to isothermal diffusion in multi-principal element alloys  

作　　者：Xin Li Dexu Cui Jianbao Zhang Zhiyuan Huang Haifeng Wang Yuhong Zhao Weimin Liu 

机构地区：[1]State Key Laboratory of Solidification Processing,Center of Advanced Lubrication and Seal Materials,Northwestern Polytechnical University,Xi’an 710072,China [2]School of Materials Science and Engineering,North University of China,Taiyuan 030051,China [3]State Key Laboratory of Solid Lubrication,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000,China

出　　处：《Journal of Materials Science & Technology》2024年第30期215-226,共12页材料科学技术(英文版)

基　　金：the Natural Science Foundation of China(Nos.51975474 and 52304414);the Fundamental Research Funds for the Central Universities(No.3102019JC001).

摘　　要：The thermodynamic extremal principle incorporating the constraints from both fluxes and forces pro-posed in part I was applied to isothermal diffusion in multi-principal element alloys(MPEAs)to propose the so-called double-constraint model.The model cannot reduce physically to the previous model con-sidering only the constraint from fluxes(i.e.,the single-constraint model)but in special cases reduces to Fick’s law and Darken’s equation,showing its reliability.Similar to the previous pair-wise model and single-constraint model,the solutes and solvent do not need to be defined in advance in the double-constraint model and the model can be also applied directly to diffusion in MPEAs.Applications to isothermal diffusion in CoCrFeMnNi pseudo-binary diffusion couple and CoCrFeNi,CoCrFeMnNi body-diagonal diffusion couples showed that the present double-constraint model overall predicted better the experimental results than the previous single-constraint model,indicating again the necessity to consider the constraints from both fluxes and forces in the phenomenological theory of Onsager.

关 键 词：Thermodynamic extremal principle Diffusion Phenomenological theory of Onsager Multi-principal element alloys 

分 类 号：TG1[金属学及工艺—金属学]