|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Environmentally Assisted Cracking: Theory and Practice
||Hydrogen and Dislocation Assisted Grain Boundary Crack Initiation Mechanism
||Liang Wan, Wen-Tong Geng, Nobuyuki Ishikawa, Hajime Kimizuka, Shigenobu Ogata
|On-Site Speaker (Planned)
Hydrogen atoms absorbed by metals in the hydrogen-containing environments can lead to the premature fracture of the metal component used in load-bearing conditions, and it often causes catastrophic failure in engineering practice. While metals used in practice mostly exist as polycrystals, the grain boundaries (GBs) can play an important role in hydrogen embrittlement of metals. Here we show that reaction of GB with lattice dislocations is a key component in hydrogen embrittlement mechanism for polycrystalline metals. We use atomistic modeling method to investigate the mechanical response of GBs in alpha-iron with various hydrogen concentrations. Analysis indicates that dislocations absorption 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 attracts more hydrogen and can greatly facilitate void nucleation and crack initiation at the GB.
||Planned: Supplemental Proceedings volume