Effect of V on microstructure and properties of Fe1.25CoNiAlMn0.21Vx magnetic high-entropy alloys

The mechanism of performance enhancement of magnetic high-entropy alloys (MHEAs) under powder metallurgical processes is unknown, especially in terms of precipitated phases. This work reports the doping behavior of Fe1.25CoNiAlMn0.21Vx (x = 0, 0.2 and 0.5) MHEAs, caused by the change of V content. Fe1.25CoNiAlMn0.21Vx MHEAs were prepared by the mechanical alloying (MA) and the spark plasma sintering (SPS). Special attention was paid to the effect of the V content on the microstructure evolution, hardness, compressive strength, and magnetic properties of HEAs. Interestingly, the phase structure of these alloys remained relatively stable regardless of the variation in V content. The addition of a small amount of V helps to increase the saturation magnetization Ms of the alloy up to 117.2 emu/g and also promotes the solid-solution strengthening effect, with a maximum compression strength of 2724 MPa and a hardness of 531 HV. The excess V atoms could not completely enter the FCC phase to form a solid solution, but would instead and form a tough and brittle phase, reducing the mechanical properties of the alloy.