Magnetic behaviour of FeCo-2V under applied stress and elevated temperature

FeCo-2V alloys are promising candidates for high-performance electric machines, such as those used in aerospace and electrification, owing to their exceptional saturation magnetisation and potential to maximise power density. Nevertheless, their magnetic behaviour under mechanical loading and at elevated temperatures remains insufficiently understood. In this study, the stress- and temperature-dependent magnetic and electrical properties of FeCo-2V were investigated separately, with particular attention to coercivity, core losses, and underlying mechanisms. Stress-dependent experiments revealed three distinct regimes. Under compressive loading, magnetic performance deteriorated, as shown by expanding hysteresis loops and increased coercivity and core losses due to hard-axis magnetisation. In the tensile regime below ∼100 MPa, performance improved through stress-assisted easy-axis alignment. At higher tensile stresses, however, micro-yielding dominated: increasing Kernel Average Misorientation (KAM) angles indicated enhanced dislocation densities, which in turn degraded magnetic properties. Independent temperature-dependent studies demonstrated that coercivity decreases systematically with increasing temperature, attributed to reduced anisotropy energy that facilitates domain wall motion. Core losses also declined with temperature, with loss-separation analysis confirming reductions in both hysteresis and eddy current loss coefficients. Additionally, electrical resistivity was observed to increase with temperature, consistent with the Drude model and a reduced eddy current loss coefficient.