The helium effect at grain boundaries in Fe-Cr alloys: A first-principles study

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• 作者：M.R. Zemła^a ; ^{marcin.zemla@wimpw.edu.pl} ; J.S. Wró ; bel^a ; T. Wejrzanowski^a ; D. Nguyen-Manh^b ; K.J. Kurzydłowski^a
• 关键词：First-principles calculations ; Iron-chromium ; Grain boundary ; Helium segregation ; Magnetic properties
• 刊名：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
• 出版年：2017
• 出版时间：15 February 2017
• 年：2017
• 卷：393
• 期：Complete
• 页码：118-121
• 全文大小：685 K
• 卷排序：393

文摘

Helium is produced in the structural materials in nuclear power plants by nuclear transmutation following neutron irradiation. Since the solubility of helium in all metals is extremely low, helium tends to be trapped at defects such as vacancies, dislocations and grain boundaries, which cause material embrittlement. Density functional theory (DFT) calculations were performed in order to investigate the helium effect at grain boundaries (GBs) in iron-chromium alloys. Both cohesive energy and magnetic properties at symmetric Σ3(1 1 1) and Σ5(2 1 0) tilt Fe GBs are studied in the presence of Cr and He atoms. It is found that the presence of Cr atoms increases cohesive energy, at different He concentrations, and strongly influences magnetic properties at the GBs. The effect of the segregation energy of helium atom as a function of the different positions of Cr atoms located inside/outside a GB has been considered. Results of the present first-principles study enable one to clarify the role of Cr in understanding the helium effect in Fe-Cr-based alloys.