The structures which were introduced by deformation at various temperatures in the anomalous strengthening region of single crystals were studied by means of high-voltage electron microscopy. Particular care was taken to preserve the bulk structure after deformation. The 3-dimensional dislocation structures which were observed by using stereo-microscopy were analyzed and were correlated with high-temperature strengthening. It was shown that the rapid work hardening which led to anomalous strengthening was essentially controlled by Kear-Wilsdorf locking or (010) cross-slip, and was not affected by secondary slip. The origin of the transition in strain-rate sensitivity was also considered, and was attributed to a transition in the hardening mechanism due to (010) cross-slip.

Rapid Work Hardening Caused by Cube Cross Slip in Ni3Al Single Crystals. Jumonji, K., Ueta, S., Miyahara, A., Kato, M., Sato, A.: Philosophical Magazine A, 1996, 73[2], 345-64