The short range ordered (SRO) structure in Ni4Mo has been investigated by means of high resolution transmission electron microscopy with digital image processing and Monte Carlo simulation. High resolution transmission electron microscope (HRTEM) images were recorded with an Imaging Plate (IP) system. Conventionally printed images of the SRO state exhibit locally dot patterns corresponding to N2M2-type (chalcopyrite-like) structure. However, the dot patterns transform into those of subunit cell clusters of D1a, D022 and Pt2Mo structures, when the image is output with a different gray scale. The Monte Carlo simulation with appropriate interaction parameters of atoms has explained successfully the HRTEM images. It is concluded that the SRO state in Ni4Mo involves subunit cell clusters of D1a, D022 and Pt2Mo structures in the atomistic level of microstructure. The concept of 〈11/20〉* static concentration waves corresponding to the N2M2 pattern is rationalized as a mesoscopically averaging view of the SRO state.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys