Synthesis and Characterization of WNiFeCo, WNiFeMo, and WNiFeCoMo Compositional Complex Alloys Manufactured by Powder Metallurgy Technique

Abstract

The WNiFeCo, WNiFeMo, and WNiFeCoMo compositional complex alloys (CCAs) were prepared by powder metallurgy technique. The thermodynamic investigations of the CCAs proved that WNiFeCo, and WNiFeMo, are medium entropy alloys (MEAs), whereas WNiFeCoMo is a high entropy alloy (HEA). The density of the prepared specimens was estimated. The sintered CCAs were characterized by investigating their microstructures and elemental distribution using SEM and EDX analysis. The crystal structure of the different phases was identified utilizing X-ray diffraction (XRD). From XRD results, W, Fe₇W_6, and FeNi were observed in all CCAs, whereas Co₇W₆, MoNi₄, and Co₇Mo₆ phases were found in WNiFeCoMo HEA. WNiFeCo MEA contained a Co₇W₆ phase, while the MoNi₄ phase was observed in WNiFeCo MEA. The A₇B₆ phases are formed in the CCAs which have good characteristics. The hardness, Young’s modulus, and corrosion behavior were evaluated. Among the investigated CCAs, WNiFeMo MEA showed the highest relative density percentage (95%), Young’s modulus (190 GPa), hardness (451 HV), and lowest corrosion rate in 3.5% NaCl (0.22 mm/y). The surface morphology of the WNiFeCo, WNiFeMo, and WNiFeCoMo alloys displayed uniform corrosion, galvanic corrosion, and localized corrosion.