A composite was prepared, using centrifugal casting, which contained a high volume fraction of D020-ordered Al3Ni. The latter phase was embedded in an Al matrix and was found to exhibit an orientation relationship which was described by (100)D020||(¯131)fcc and [010]D020||[101]fcc; where the orthorhombic D020 adopted a rod morphology with its longitudinal axis along [010]D020. It was found that Al3Ni was deformable by dislocation glide, at 300K, when Al3Ni that was embedded in a thin-foil specimen was deformed by compression. The Burgers vector and slip plane of the glide dislocations were determined to be [1l0](1¯10) perfect super-dislocations by studying visibility and g•b values in a high-voltage electron microscope. Four of the perfect dislocations were found to move as a group, with associated residual contrasts between them. For the above orientation relationship, the shear direction and plane were almost continuous across the interface between the Al3Ni and the Al matrix. It was suggested that penetration of shear deformation through the Al/Al3Ni interface played an important role in the generation of mobile super-dislocations.

Observation of Glide Dislocations in D020 Ordered Al3Ni. K.Yamashita, I.Fujimoto, T.Murakumo, S.Kumai, A.Sato: Philosophical Magazine A, 2000, 80[1], 219-35