During the interaction between a queue of dislocations and the buried interface, such as grain boundaries (GBs) and phase boundaries (PBs), in materials, a dislocation pileup usually forms, which in turn, significantly modifies the local stress state. This process is multiscale in nature since both the atomistic interface structure and the long-range stress induced by the dislocation accumulation near the interface come into play in the subsequent structure change. Taking the Ti-alloy, the hydrogen-charged steel, and the amorphous/crystalline metallic composites as model materials, here we present a concurrent atomistic-continuum method for (i) measuring not only the local Cauchy stress but also the couple stress ahead of a long-range dislocation pileup; and (ii) determining their roles in the subsequent structure change, such as phase transformation, twinning, hydrogen-induced cracking, and the shear banding, caused by the dislocation-interface reaction. Our results elucidate the discrepancies between fully atomistic simulations and experimental observations of dislocation-interface reactions, and highlight the importance of directly modeling dislocation-GB interactions using concurrent multiscale approaches.

Predicting the Dislocation-Interface Reaction and the Subsequent Structure Changes Across 6+ Length Scales

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