Three-Dimensional Interaction of {1012} Twin with Tilt Boundaries in Mg: Twin and Dislocation Transmission

摘要

While both dislocations and deformation twins accommodate plastic shear, the former are linear and the latter are three-dimensional domains bounded by complex interfaces. Therefore, the transmission of twins is much more complex than that of dislocations. In this work, we characterize the reactions and possible scenarios of associated interactions between twins and tilt boundaries using both atomistic and phase-field simulations. We find that the interaction is a competition between slip and twin transmission, depending on the geometrical alignment of the slip and/or twinning systems, resolved shear stress, and short-range interactions between intrinsic defects within the twins and grain boundaries. More importantly, we find that lateral twin transmission is easier than the forward twin transmission. We use a phase-field model to systematically investigate the role played by interfacial properties of the twin, such as facet energies and mobilities, on lateral and forward transmission into neighboring grains.