Grain-boundary segregation and grain growth in nanocrystalline substitutional solid solution alloys  

作　　者：Fawei Tang Chao Hou Hao Lu Zhi Zhao Xiaoyan Song 

机构地区：[1]Faculty of Materials and Manufacturing,Key Laboratory of Advanced Functional Materials,Ministry of Education of China,Beijing University of Technology,Beijing 100124,China

出　　处：《Journal of Materials Science & Technology》2024年第1期239-249,共11页材料科学技术（英文版）

基　　金：supported by the Beijing Natural Science Foun-dation(No.2214067);the National Key R&D Program of China(Nos.2021YFB3501502 and 2021YFB3501504);the National Natural Science Foundation of China(No.92163107).

摘　　要：A model for describing solute segregation at grain boundaries has been developed for substitutional solid solution alloys,which integrates multiple factors from atomic to microstructural scales.A concept of mo-lar Gibbs free energy of segregation was introduced to evaluate the segregating capability of the solute elements in a closed system,through which the influences of grain boundary structure,grain size,ma-terial composition,and external conditions were described.Based on the evaluation of various energy forms related to solute segregation and grain growth processes,the nature of the thermal stabilization of nanograin structures by solute segregation was disclosed.A criterion for the destabilization of nanostruc-tures,which is determined by the competition of the change rates between the molar Gibbs free energy of segregation and the total energy of grain boundaries with grain size,has been proposed.This study provided guideline to achieve high-temperature stability of nanograin structures of solid solution alloys even for the weakly segregating nanocrystalline systems.

关 键 词：Substitutional solid solution Grain boundary segregation Thermal stabilization Solute concentration Grain size 

分 类 号：TG1[金属学及工艺—金属学]