It was recalled that various models had been proposed in order to explain the flow stress anomaly in such L12 ordered compounds. These considered the anomalous increase in flow stress with temperature, the strain-rate sensitivity, the marked orientation dependence, and the tension/compression asymmetry. The most important common feature of these models was that the flow stress anomaly was assumed to be the result of the cross-slip of <110> super-dislocations from {111} to {100} planes so as to form so-called Kear-Wilsdorf locks. Computer simulations of the super-dislocation core structure in the present material indicated that the immobility of Kear-Wilsdorf locks was due to the non-planar core structure of 1/2<110> super-partials. The latter always spread their cores onto {111} planes other than the {100} antiphase boundary planes. It remained unclear how cross-slip took place. The present study revealed the atomistic process for the cross-slip of 1/2<110> super-partials from {111} to {100} planes. It was deduced from the present simulation that cross-slip of the 1/2[¯101] super-partial from (1¯11) to (010) involved core transformation between (1¯11) and (111) planes. The process had to be assisted by thermal activation.

Atomistic Process of Dislocation Cross-Slip in Ni3Al. Wen, M., Lin, D., Lin, T.L.: Scripta Materialia, 1997, 36[3], 265-8