Orientation Dependent Twinning Behavior in a Twinning-induced Plasticity Steel Investigated by Nanoindentation

The present work focuses on the mechanical behavior of single austenite grain with different orientations in a twinning induced plasticity (TWIP) steel by nanoindentation test. Deformation twins can be found in [0 0 1]-orientated grains after nanoindentation, while they are absent in grains with [1 1 1] orientation. This inconformity can be ascribed to a larger Schmid factor for leading partial dislocations compared to trailing partial dislocations on the primary slip system in [0 0 1]-orientated grains during compression. Different from deformation twins, high-density dislocations can be found in both [0 0 1] and [1 1 1]-orientated grains after nanoindentation. The present work suggests that the density of deformation twins can be enhanced by controlling crystal orientation through texture engineering or by deformation along different directions such as cross-rolling.