Microscopic and macroscopic analyses of the interaction mechanism between defect growth and dislocation emission in single-crystal aluminum

The study on the interaction between defects and dislocation emission is of significance to predict the behaviors of fracture and plastic deformation in crystalline metals; however, the multiscale interaction mechanism has not been well understood. In this work, based on molecular dynamics simulation and distributed dislocation technique, the interaction mechanism between dislocation emission and a crack or a void is studied at the atomic and continuum scales. The results show that dislocation emission can change the mode of crack growth, i.e., from brittle to ductile, and the emitted dislocations cause crack-tip blunt and decrease stress concentration near the defects. The increment of void growth is completely contributed by dislocation emission, and it can be predicted by the characteristics of dislocation emission. This work reveals the influence mechanism of dislocation emission on failure behaviors and deepens the understanding of the interaction between dislocation emission and defects.