Ni3(Al,1%Ta) single crystals were deformed in compression in the temperature range of the flow stress anomaly (300 to 770K). The strain rate sensitivity of the flow stress was examined by the stress relaxation technique. The core structures of the super-dislocations on (111) and (001) planes were observed using weak beam transmission electron microscopy. The transmission electron microscopic observations and the strain rate sensitivity tests both defined two temperature regimes over the investigated temperature range. The importance of using weak beam image simulations to derive actual antiphase boundary energies from the experimental observations was emphasized.

On the Relationship between Unusual Mechanical Properties and Deformation Substructures in Ordered Ni3Al. Baluc, N., Bonneville, J., Hemker, K.J., Martin, J.L., Schäublin, R., Spätig, P.: Materials Science and Engineering A, 1993, 164[1-2], 379-83