Atomistic insights into hydrogen-enhanced strain-induced vacancy in α - iron across varied strain rates

Abstract

Dynamic behavior of α-iron in the presence of hydrogen (H) under triaxial tension is investigated by molecular dynamic simulations. The process of hydrogen enhanced strain induced vacancy is directly captured at the atomic scale in a wide range of strain rates. Significant strain rate effects and H concentration dependence are observed in the hydrogen embrittlement of α-iron. When the concentration of H ($C_H$) is substantially high, the maximum tensile stress of iron falls. More local phase transitions are observed at the aggregation sites of H atoms, which plays a crucial role in ensuring that the material does not lose its load bearing capacity immediately after reaching the maximal stress. Our study sheds light on the intricate interplay of H, strain rate, phase transition (PT) in α-iron and provides valuable insights into the complex dynamics of H embrittlement.