The Fe-Cr-Co alloys without and with either 0.96 Wt%, 2.28 Wt% or 3.14 Wt%. Mo were prepared to study the effect of Molybdenum on shape anisotropy of $\alpha_1$ particles induced by the interaction of elastic strain and the applied external stress during spinodal decomposition treatment.
The degree of shape anisotropy of $\alpha_1$ particles were indirectly measured by magnetic properties and some of the sample were directly measured by transmission electron microscopy. The stress induced shape anisotropy of $\alpha_1$ particles were observed in Fe-Cr-Co system but the shape anisotropy parallel to the applied stress direction were not observed in Fe-Cr-Co alloys with more than 0.96 Wt% Molybdenum. This was interpreted as the elastic strain energy associated with the phase separation along a certain crystallographic plane becomes large compare to the elastic interaction energy associated with applied elastic stress and volume change accompanied by phase separation by Molybdnenum addition. It was, therefore, concluded that Molybdenum addition in Fr-Cr-Co system increases elastic crystalline anisotropy. This was confirmed for the specimens heat treated under strong magnetic field. This phenomenon was discussed by mean of electron micrographs and magnetic properties measurements.