1. Effect of H on the formation of vacancy dislocation loops in α-Fe.
- Author
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Pan, Xin-Dong, Lu, Tao, Lyu, Yi-Ming, Xu, Yu-Ping, Zhou, Hai-Shan, Yang, Zhong-Shi, Niu, Guo-Jian, Li, Xiao-Chun, Gao, Fei, and Luo, Guang-Nan
- Subjects
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DISLOCATION loops , *VACANCIES in crystals , *ATOM trapping , *BINDING energy , *GENETIC algorithms , *STATICS - Abstract
• A possible mechanism for the formation of vacancy dislocation loops in α-Fe is proposed. • Vacancy-NH clusters prefer to shape into 2D clusters, especially on (211) planes. • The presence of H can greatly promote the growth of vacancy dislocation loops. Genetic algorithm was applied to search the energy minimization configuration of vacancy clusters in α-Fe. Molecular statics calculations and dynamics annealing relaxation were employed to calculate the formation and binding energies of vacancies and 3D vacancy or vacancy-hydrogen (H) clusters, as well as 2D vacancy or vacancy-H clusters on (111), (011) and (211) planes. Our calculations show that vacancies prefer to form 3D clusters and vacancy dislocation loops are difficult to form, while vacancy-H clusters prefer to shape into 2D clusters, especially on (211) planes. Since H prefers the directional bonding, a vacancy cluster with H atoms tend to form a vacancy dislocation loop with its slip direction along the 〈100〉 direction and on the (211) habit plane. Our results are consistent with the experimental observations, and provide a possible mechanism for the formation of vacancy dislocation loops in α-Fe. Furthermore, we have also explored how dislocation loops trap self-interstitial atoms, vacancies and H atoms. It is of interest to note that H atoms strongly bound to a 〈100〉 vacancy dislocation loop, and are able to enhance the ability for the dislocation loop to further trap vacancies and reduce its ability to absorb self-interstitial atoms, thus promoting the growth of the 〈100〉 vacancy dislocation loops. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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