A Molecular dynamics study on hydrogen embrittlement of a grain boundary in alpha-iron

鉄の水素粒界脆化に関する分子動力学法による研究

門吉 朋子; 蕪木 英雄; 板倉 充洋  ; 山口 正剛   

Kadoyoshi, Tomoko; Kaburaki, Hideo; Itakura, Mitsuhiro; Yamaguchi, Masatake

The hydrogen embrittlement has been known for over a century when metals are under corrosive, welding, and irradiation conditions, however, its mechanism has not yet been precisely identified. It is empirically established that steels are susceptible to hydrogen embrittlement as the tensile strength exceeds approximately 1 GPa. In particular, it is shown in recent experiment of high strength steels that a clear crossover in fracture mode from quasi-cleavage to intergranular fracture is observed as a function of charged hydrogen bulk concentration. Here, we concentrate on studying the grain boundary embrittlement of -iron in the high hydrogen concentration region. Molecular dynamics method is mainly employed to study decohesion properties of a 3 grain boundary in the presence of hydrogen. A newly developed empirical potential of Fe-H is used based on the empirical Fe potential.