On the role of incomplete Kear-Wilsdorf locks in the yield stress anomaly of Ni3Al

In situ straining experiments in an Ni-25.9at.% Al alloy at room temperature indicate that the density of incomplete Kear-Wilsdorf locks is high during deformation. The model of mechanical properties which is based on their unlocking by an intrinsic cross-slip process is described, and compared with the alternative kink model. The results indicate that the alloy investigated has a higher complex stacking fault energy than stoichiometric Ni3Al.