J. Mater. Sci. Technol. ›› 2021, Vol. 93: 169-177.DOI: 10.1016/j.jmst.2021.02.046

• Original article • Previous Articles     Next Articles

Research Article Capture efficiency and bias from the defect dynamics near grain boundaries in BCC Fe using mesoscale simulations

Jun Chaia,b, Shuo Jin a,b, Ziang Yuc,d, Haixuan Xu c,d,**(), Guang-Hong Lua,b,*()   

  1. aSchool of Physics, Beihang University, Beijing 100191, China
    bBeijing Key Laboratory of Advanced Nuclear Materials and Physics, Beihang University, Beijing 100191, China
    cDepartment of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, United States
    dJoint Institute for Advanced Materials, Knoxville, TN 37996, United States
  • Accepted:2020-12-16 Published:2021-12-10 Online:2021-12-10
  • Contact: Haixuan Xu,Guang-Hong Lu
  • About author:lgh@buaa.edu.cn (G.-H. Lu).
    **Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, United States. E-mail addresses: xhx@utk.edu (H. Xu),

Abstract:

The capture efficiency describes the capability of a sink, such as a grain boundary (GB), dislocation, and void, to absorb point defects (PDs). The bias defines the difference in capture efficiency between the absorption of a vacancy and dumbbell at a sink. Complete kinetic information on PDs, including diffusion barriers and diffusion orientations, as well as accurate saddle points, are needed to determine the capture efficiency and bias at a sink accurately, which is computationally demanding. In the present study, the Self-Evolving Atomistic Kinetic Monte Carlo (SEAKMC) method was used to investigate the defect dynamics of PDs near different types of grain boundaries (GBs) (with both 〈100〉 and 〈110〉 families) accurately in body-centered cubic (BCC) iron (Fe). The capture efficiency, sink strength, and bias factor of different types of GBs were determined in Fe, which, different from traditional rate theory estimation, showed a distinct capture efficiency, sink strength, and bias in different GBs. The results demonstrate a strong positive correlation between the capture efficiency and the GB strain width, instead of the GB misorientation, GB energy, or GB-PD binding energy, which have been investigated previously. This work provides valuable insight into the radiation-induced microstructural evolution of GBs.

Key words: Iron, Grain boundary, Capture efficiency, Bias, SEAKMC