The effect of heat treatment on the metallurgical properties of FeCo alloy

Fe-Co alloys, in particular B2 FeCo, are considered attractive soft materials due to their superior properties, particularly their high saturation magnetization and mechanical strength in applications such as electricity powerlines, aerospace and automotive industries. Despite its application potential, B2 FeCo alloy is characterized by limited ductility at room temperature. In this study, the effect of heat treatment on the constituent phases, microstructures and micro-Vickers hardness of FeCo alloy is investigated. Phase and microstructural evolution were tracked using X-ray diffractometer (XRD) and optical microscope (OM), respectively. The X-ray analysis of the as-cast condition (AC) and furnace cooling (FC) displayed α’-B2 phase peaks with traces of α phase while ice-water quenched (WQ) at 750 °C and 1000 °C showed only α phase. OM of WQ at 750 °C samples showed wide equiaxed α’ grains, while the AC, WQ (1000 °C) and FC demonstrated finer grains inside and around the grain boundaries. Other metallurgical analyses carried out include micro-Vicker hardness tests, from which the WQ (1200 °C) sample demonstrated the highest hardness value as compared to both AC and FC samples.