The Impact of Structural Units on Copper Grain Boundary–Dislocation Interactions

A molecular dynamics approach was employed to investigate the interaction behavior between tilt-[110] copper grain boundaries (GBs) and dislocations, with particular emphasis on elucidating the role of GB structural unit (SU) types in the mechanisms of dislocation absorption and transmission. The results reveal that singular GBs composed of continuous and uniform B-type or C-type SUs exhibit a pronounced ability to absorb dislocations, whereby incident dislocations are fully absorbed by the GB and prevented from transmitting across it. In contrast, for discrete GBs containing both C SUs and intrinsic stacking fault facets, the dislocation accommodation capacity of the GB is closely related to the number of C SUs within the discrete region. Multiple continuous C SUs can effectively facilitate dislocation absorption and energy dissipation through a synergistic linkage mechanism. This study underscores the critical role of GB SUs in governing GB–dislocation interactions and provides atomic-scale insights into the microstructural regulation mechanisms of GBs during plastic deformation.