Strain Softening of Aluminum in Shear at Elevated Temperature

Large-strain deformation of aluminum in shear consistently evinces strain softening of roughly 15-20%. Most researchers have suggested that this flow stress decrease is a consequence of a decrease in the average Taylor factor as a consequence of a shear-texture. The authors also consider, now, the possibility that changes in the dislocation climb stress induced by the texture could rationalize the softening. This work reports on an analysis of large strain deformation of aluminum single crystals in the softest orientation {111} <110>. Here softening is not observed. However, this result and other in earlier publications are consistent with dislocation climb being the rate-controlling process that also explains the observed stress versus strain behavior.