Abstract
There are great expectations to hydrogen as a next generation energy or a medium of energy. However, it is well known that hydrogen weakens the strengths of metals. Despite the extensive investigations concerning hydrogen related fractures, the mechanisms have not been enough clarified yet. The difficulties to reveal the essential effects of hydrogen are mainly attributed to the characteristics of hydrogen such as ppm-order extremely low concentration, high diffusivity and high sensitivity to the defect-densities in metals. In this study, we applied molecular dynamics (MD) simulations to Mode I crack growth in α-iron single crystals with and without hydrogen, and analyzed the hydrogen effects from the atomistic viewpoints. We propose the mechanism of hydrogen related slip plane fracture based on the interaction between hydrogen atoms and dislocations around the crack tip.
