Tailoring mechanical and magnetic properties of AlCoCrFeNi high-entropy alloy via phase transformation

Phase constitutions, either changed by alloying or by phase transformation, are the key factors to determine the magnetic and mechanical performances of high-entropy alloys (HEAs). Using the AlCoCrFeNi HEA as a candidate alloy, this paper demonstrates the effect of phase transformation on both the mechanical and magnetic properties in the multi-phase system. With increasing heat treatment temperature, the sigma (sigma) and face-centered-cubic (FCC) phases disappeared at 1000 degrees C and 1200 degrees C, respectively. Such volume fraction changes of sigma, FCC and body-centered-cubic (BCC) phases have divergent effects on mechanical and magnetic properties. The excellent strength-ductility combination will be achieved as the disappearance of sigma phase and formation of FCC phase. As for the magnetic properties, the volume fraction of BCC phase plays a major role in determining its saturation magnetization. When the volume fraction change of BCC phase is not evident, the higher volume fraction of FCC phase will influence its magnetization at 2 T. Our present work might provide insights into analyzing the evolution of both mechanical and magnetic properties of HEAs caused by complex phase transformation. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.