FeAl multilayers by sputtering: heat treatment and the phase evolution

Multilayers of Fe and Al corresponding to the composition Fe58A142 (equal layer thickness) have been deposited by sputtering. The as-deposited layers have been characterised by X-ray diffraction (XRD) techniques and transmission electron microscopy (TEM) to determine the initial phases present. The results indicate the presence of both the elements and there is no evidence for any intermetallics to be present in the as-deposited films. The evolution and transformation of these elemental multilayers to intermetallic compound on heating is studied using differential scanning calorimetry (DSC) coupled with XRD and TEM techniques. The results of solid state heat treatment are compared to that of laser mixing carried out on these samples. Attempts are made to understand the sequence of the observed phases from the knowledge of thermodynamics and kinetics.