The 9th International Conference on Multiscale Materials Modeling

講演情報

Poster Session

E. Deformation and Fracture Mechanism of Materials

[PO-E1] Poster Session 1

Symposium E

2018年10月29日(月) 17:45 〜 20:00 Poster Hall

[P1-22] Hydrogen embrittlement controlled by reaction of dislocation with grain boundary in alpha-iron polycrystals

Liang Wan1,2, Wen Tong Geng2,3, Akio Ishii2, Jun-Ping Du2,4, Nobuyuki Ishikawa5, Hajime Kimizuka2, Shigenobu Ogata2,4 (1.Wuhan University, China, 2.Osaka University, Japan, 3.University of Science and Technology Beijing, China, 4.Kyoto University, Japan, 5.JFE Steel Corporation, Japan)

Hydrogen atoms absorbed by metals in the hydrogen-containing environments can lead to the premature fracture of the metal components used in load-bearing conditions. Since metals used in practice are mostly polycrystalline, grain boundaries (GBs) can play an important role in hydrogen embrittlement of metals. Here we show that the reaction of GB with lattice dislocations is a key component in hydrogen embrittlement mechanism for polycrystalline metals. We use atomistic modeling methods to investigate the mechanical response of GBs in alpha-iron with various hydrogen concentrations. Analysis indicates that dislocations impingement and emission on the GB cause the GB to locally transform into an activated state with a more disordered atomistic structure, and introduce a local stress concentration. The activation of the GB segregated with hydrogen atoms can greatly facilitate decohesion of the GB. We show that the hydrogen embrittlement model proposed here can give better explanation of many experimental observations.