A study was made of the defects which were typical of the faceted interfaces that were associated with the orientation relationships, (11¯1)Ni3Al||(010)Ni3Nb and [1¯10]Ni3Al||[100]Ni3Nb. High-resolution electron microscopy revealed the presence, along the same interface, of ledges which separated facets having differing atomic structures. Some facets were associated with certain interfacial thicknesses because their structures involved one planar fault or an intermediate ultra-thin Ni3Al crystal. The observed ledges were associated with a misfit dislocation with b = (-1/6)[112] Ni3Al. This vector was determined by comparing experimental images with simulated images. Use of the multi-slice method accounted for the elastic field which surrounded each misfit dislocation core.

Misfit Dislocations Associated with Ultrathin Twins along a Ni3Al/Ni3Nb Interface. Bonnet, R., Loubradou, M., Dahmen, U., Hinderberger, S.: Materials Science Forum, 1996, 207-209, 201-4