Orientation dependent hardening of {111} plate precipitate by parametric dislocation dynamics

The effects of the orientation, geometry of slip plane, existence of cross slip on the dislocation interaction with a {111} plate precipitate has been investigated by parametric dislocation dynamics based on Green’s function method. The dislocation bypassing process is greatly influenced by the geometrical relation of the {111} precipitate and the dislocation Burgers vector, where the internal stress of the misfitting precipitate is found to be critical to the orientation dependent hardening behaviour of the {111} precipitation variants classified as Type-A (intersected by 0 deg.), Type-B (intersected by 60 deg.) and Type C variant (parallel to slip plane). The energy analysis reveals that the orientation dependent hardening in the simulated stress strain curves is attributed to the topological change in the dislocation microstructure influenced by the internal stress around {111} variants, where the cross slip enhances the increase of the dislocation self-energy. Hence, the simultaneous hardening mechanism by the misfit precipitates and dislocations is suggested.