Interplay between vacancy-induced hydrogen segregation and stress-induced vacancy redistribution causing embrittlement of alpha-iron.

This study proposes a novel mechanism of intergranular fracture in alpha-iron, focusing on the effects of trapped vacancies, H atoms, and their synergistic interplay under tensile strain. We present a methodology for the introduction of H into grain boundaries (GBs) resulting in a realistic distribution by considering H-H interactions. Accordingly, optimal H concentrations were determined under specific environmental conditions for GBs with and without vacancy-induced segregation under zero and 2% tensile strain, respectively.