Effect of Homogenization on Microstructure, Thermal, and Mechanical Properties of Arc-Melted AlFeCrNi Medium Entropy Alloy

Abstract

The low-cost, cobalt-free bulk AlFeCrNi medium entropy alloy (MEA) was produced using the argon arc melting method, utilizing a cold-compacted pellet as the raw material. The microstructural analysis, phase analysis, and mechanical properties of the as-cast MEA were examined and compared with those of the homogenized AlFeCrNi MEA. Both as-cast and homogenized samples were characterized using x-ray diffraction and scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy (EDS). The mechanical properties were assessed based on hardness and compressive strength. X-ray diffraction analysis reveals that in both the as-cast and homogenized AlFeCrNi MEA exhibits the ordered B2 phase and a disordered type BCC structure. Energy-dispersive spectroscopy (EDS) identified the ordered phase as NiAl intermetallics, while the disordered phase corresponds to a (Fe, Cr) solid solution. A strong agreement is observed between the criteria for forming multi-component alloys and the theoretical structure predictions. The DSC analysis confirms the absence of phase transformations in the as-cast MEA up to 1000 °C. The microhardness of the as-cast and homogenized MEA is measured at 504.9 ± 11.44 HV and 436 ± 10.78 HV, respectively, while their compressive yield strength is 1255.61 MPa and 1134.46 MPa. Both variants exhibit a strain exceeding 50%. © 2025 Elsevier B.V., All rights reserved.