Atomistic modeling of He embrittlement at grain boundaries of α-Fe: A common feature over different grain boundaries

摘要

He atoms introduced into materials may lead them to fracture intergranularly, and understanding such an effect is a key issue in the design of future fusion reactors. In the current study, we investigated the decrease of grain boundary (GB) strength caused by He segregation at several kinds of α-Fe GBs by exploiting first principles calculations and a set of empirical potentials. We found enough evidence to support the notion that the GB cohesive energy, a critical measure of GB strength, approximately scales with the He concentration at the GB surface, regardless of the GB type.