On short range order and micro-domains in the Ni 4Mo system

Abstract

Electron diffraction and field ion microscopy have been used to investigate the nature of short range order in as quenched Ni 4Mo. The results indicate that the as quenched state consists of an assembly of micro-domains possessing the six orientational variants of the Ni 4Mo superstructure. The 1 1 2 0 diffuse peaks have been attributed to the occurrence of non-conservative anti-phase boundaries within the micro-domains. A similar argument is used to account for the occurrence of 1 1 2 0 peaks in the disordered α-phase at other compositions in the NiMo system.