On the conversion of plastic work to heat in Mg alloy AZ31B for dislocation slip and twinning deformation

In this study the conversion of plastic work to heat of a hot-rolled magnesium alloy AZ31B is investigated using a mechanism-based approach. Shear-compression specimen loading orientations are selected to promote plastic deformation principally through either basal slip, combined pyramidal and prismatic slip, or extension twinning. Loading orientations were selected based on predictions from a crystal plasticity model. High strain-rate adiabatic deformation was accomplished using a compression Kolslcy bar. During each experiment the deforming gauge section temperature rise is recorded using a single-point infra-red detector. From the specimen deformation, thermal measurements, and crystal plasticity calculations of mechanism activity, the conversion of plastic work to heat was inferred. Specimens where basal, prismatic, and pyramidal slip accounted for the majority of plastic deformation exhibited similar percentage of plastic work converted to heat. Specimens where extension twinning was highly active exhibited a comparatively lower fraction of plastic work converted to heat.