CUBE SLIPS AND ANOMALOUS STRENGTHENING IN NI3GE SINGLE-CRYSTALS

Strengthening mechanisms of Ni3Ge single crystals have been studied by compression tests below and above the peak temperature where the anom alous strengthening due to octahedral slip involving cube cross-slip c hanges to primary cube slip. From the three-dimensional analysis of th e dislocation structure after deformation, it is revealed that the sup erdislocations take Various configurations depending on the test tempe rature and the starting dislocation structure introduced by pre-strain ing at different temperatures. It is also confirmed that the anomalous strengthening appears in a wide temperature range by octahedral slips for the [001] compression. Based on these observations, origin of the striking strengthening in Ni3Ge is attributed to the cube cross-slip and the resultant complex dislocation structure below the peak tempera ture, and the primary cube slip involving dislocation climb above it.