Magnetic and thermal properties of CoFeNi-based high entropy alloys

The first generation of High Entropy alloys (HEAs) is that five or more equiatomic components are fabricated together in the range of 5-35 at.% concentration. Recently, the second generation of HEAs was identified as non-equimolar compositions. HEAs have outstanding mechanical properties with excellent magnetic behaviour that may be changed further by adding various alloying elements. This study investigated the influences of adding elements (Ti, Cr, Sn, V, Hf, Ga) on AlCoFeMnNi alloy's structure and magnetic properties. Many different measurements were performed for the alloys, including scanning electron microscope, energy-dispersive X-ray (SEM-EDX) were used to structure analysis, and X-ray diffraction (XRD) was used for crystal structure examinations. Besides, thermal analyses were carried out through differential thermal analysis (DTA). Above all, vibrating sample magnetometry (VSM) is used to verify its applicability in magnetic applications. In equiatomic AlCoFeMnNi alloy, the highest magnetization value has been seen, which is 141.1 emu/g, while the lowest value (51.2 emu/g) was detected through Hf addition AlCoFeMnNi alloy. The change in magnetic characteristics is due to the phase change related to different element additions. The results obtained through materials analysis have been reported by examining HEAs' structural, thermodynamic, and magnetic aspects. In addition, it is calculated that the tested alloys have a coercivity in the range of 78 Oe to 325 Oe, which means the produced alloys have semi-hard magnetic behaviour. All results should guide how these alloys could be used in magnetic applications.