title: The thermal stability of the nanograin structure in a weak solute segregation system.
abstract: A hybrid model that combines first principles calculations and thermodynamic evaluation was developed to describe the thermal stability of a nanocrystalline solid solution with weak segregation. The dependence of the solute segregation behavior on the electronic structure, solute concentration, grain size and temperature was demonstrated, using the nanocrystalline Cu-Zn system as an example. The modeling results show that the segregation energy changes with the solute concentration in a form of nonmonotonic function. The change in the total Gibbs free energy indicates that at a constant solute concentration and a given temperature, a nanocrystalline structure can remain stable when the initial grain size is controlled in a critical range. In experiments, dense nanocrystalline Cu-Zn alloy bulk was prepared, and a series of annealing experiments were performed to examine the thermal stability of the nanograins. The experimental measurements confirmed the model predictions that with a certain solute concentration, a state of steady nanograin growth can be achieved at high temperatures when the initial grain size is controlled in a critical range. The present work proposes that in weak solute segregation systems, the nanograin structure can be kept thermally stable by adjusting the solute concentration and initial grain size.
authors.affiliation: College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Beijing university of Technology, Beijing 100124, China. xysong@bjut.edu.cn.
authors.forename: Fawei
authors.initials: F
authors.lastname: Tang
authors.affiliation: College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Beijing university of Technology, Beijing 100124, China. xysong@bjut.edu.cn.
authors.forename: Xiaoyan
authors.identifier: http://orcid.org/0000-0003-3844-729X
authors.initials: X
authors.lastname: Song
authors.affiliation: College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Beijing university of Technology, Beijing 100124, China. xysong@bjut.edu.cn.
authors.forename: Haibin
authors.initials: H
authors.lastname: Wang
authors.affiliation: College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Beijing university of Technology, Beijing 100124, China. xysong@bjut.edu.cn.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Beijing university of Technology, Beijing 100124, China. xysong@bjut.edu.cn.
authors.forename: Zuoren
authors.initials: Z
authors.lastname: Nie