Straining experiments were performed on the oxide dispersion-strengthened Ni-based superalloy at 1020 or 1065K. Dislocations were pinned at the particles, and bowed out between them. Upon breaking free from the particles, the dislocations exhibited viscous behaviour. At low average dislocation velocities, the waiting time between full bowing-out and detachment was longer than the time for motion between the particles and bowing-out. This suggested that the interfacial pinning mechanism was rate-controlling. At higher velocities, the waiting-time was short; compared with that for bowing-out. The particles nevertheless impeded dislocation motion, due to the back-stress which resulted from bowing.

HVTEM in situ Observations of Dislocation Motion in the Oxide Dispersion Strengthened Superalloy MA754. D.Häussler, M.Bartsch, U.Messerschmidt, B.Reppich: Acta Materialia, 2001, 49[18], 3647-57