中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 24 No. 12 December 2014 |
（1. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;
2. Institute for Special Steels, Central Iron and Steel Research Institute, Beijing 100081, China）
Abstract:The observations of grain-boundary segregation of Bi in Cu bicrystals were analyzed. According to equilibrium grain boundary segregation (EGS) model and non-equilibrium grain-boundary segregation (NGS) model, respectively, the segregation kinetics of isothermal annealing at 500 °C and that of isochronal annealing for 24 h of Bi in Cu bicrystals were investigated. By qualitative analysis and quantitative analysis, it is concluded that the grain-boundary segregation of Bi agrees well with the theory of NGS. Based on the kinetics model of NGS, some parameters that are useful to predicting and controlling the Bi-induced embrittlement in Cu alloys are calculated as follows: the diffusion coefficient of Bi-vacancy complexes Dc=7.8×10-5exp[-1.46/(kT)]; the apparent diffusion coefficient of Bi atoms DiA=7.66×10at+bexp[–1.76/(kT)], where a=8.45×10-8 and b=-13.37.
Key words: bismuth; copper; segregation; grain boundary; diffusion
