Abstract Scope |
We have performed a comprehensive investigation of symmetry breaking in the interactions between dislocation and various superlattice planar faults in intermetallic alloys, to reveal the underlying dislocation mechanisms that govern intrinsic plastic deformation asymmetry, employing both large-scale atomistic simulations and continuum dislocation theory. Ni-based and Ti-based alloys, of different crystal structures, were examined, with two primary symmetry breaking effects, i.e., translational and three-fold rotational symmetry breaking considered. Detailed asymmetrical dislocation reactions and the corresponding dislocation bypassing mechanisms have been elucidated, shown to be highly dependent on the geometrical configuration of the precipitate and the relative magnitudes of fault energies. A continuum model framework was then developed, which, for the first time, provides accurate and quantitative predictions of the threshold conditions triggering critical asymmetrical dislocation slips, verified to be in good agreement with the simulation results. The findings provide critical new understanding of deformation asymmetry in intermetallic alloys. |