Dislocation structures in deformed CoO and MnO

Abstract

Transmission electron microscopy (TEM) and etch-pitting techniques have been used to examine dislocation structures of CoO and MnO single crystals deformed into steady state from 1000 to 1400° C. In this temperature range, studies have shown that there are low- and high-temperature activation energies (Q) and stress exponents (n). No change was observed in the structures of samples deformed within this temperature range. It is concluded, therefore, that any change inQ andn values is due to a change in oxygen diffusion path from the bulk at higher temperatures to along dislocation cores at lower temperatures, rather than being due to a change in the rate-controlling mechanism of deformation