Transmission electron microscopic in-situ straining experiments were performed on thin foils of Ni3Al and Ni3Al containing 750ppm (0.35at%) boron. During the straining, gliding antiphase boundary-coupled dislocations were observed to leave superlattice intrinsic stacking faults as debris in their wake confirming a mechanism for superlattice intrinsic stacking fault formation first suggested by Pak et al. (1976). The antiphase boundary-coupled dislocations piled up at grain boundaries, became extrinsic grain boundary dislocations and initiated slip in adjacent grains. The characteristics of the crack propagation process indicated that plastic flow, albeit localised, preceded fracture.

In situ Straining of Ni3Al in a Transmission Electron Microscope. Baker, I., Schulson, E.M., Horton, J.A.: Acta Metallurgica, 1987, 35[7], 1533–41