Interfaces in ordered intermetallics

Abstract

In this paper, we have examined different types of interfaces that occur between orientational/translational variants generated during the ordering process. This has been illustrated citing examples of ordering of the FCC structure into DO₂₂, Dl_a and Pt₂Mo type structures in some nickel base alloys. Microstructures consisting of more than one ordered structure have also been investigated. Superlattice domains of DO₂₂ and Pt₂Mo type structures have also been found to coexist in a microscopic scale of mixing in Ni-V alloys while mixed domains of Dl_a and Pt₂Mo type structures on a much finer scale have been observed in Ni-Mo alloys. The formation of different variants (rotational and translational) of ordered structure(s) from the disordered lattice has been explained on the basis of group theoretical and symmetry considerations.