Microstructure and Mechanical Properties of $$\hbox {CoCrFeNi}_{2}\hbox {Al}_{1{-}{x}}\hbox {W}_{{x}}$$ CoCrFeNi 2 Al 1 - x W x High Entropy Alloys

Abstract

The microstructures, phase composition, and mechanical properties of the $$\hbox {CoCrFeNi}_{2}\hbox {Al}_{1{-}{x}}\hbox {W}_{{x}}$$ (x: molar ratio, $${x} = 0,~0.1,~0.2$$ , and 0.3) high entropy alloys were investigated. Only BCC phase and FCC phase were found in $$\hbox {CoCrFeNi}_{2}\hbox {Al}_{1{-}{x}}\hbox {W}_{{x}}$$ alloys. Thereinto, the $$\hbox {CoCrFeNi}_{2}\hbox {Al}$$ alloy was comprised of the primary phase with BCC structure and the eutectic structures with BCC and FCC phases. The $$\hbox {CoCrFeNi}_{2}\hbox {Al}_{0.9}\hbox {W}_{0.1}$$ , $$\hbox {CoCrFeNi}_{2}\hbox {Al}_{0.8}\hbox {W}_{0.2}$$ , and $$\hbox {CoCrFeNi}_{2}\hbox {Al}_{0.7}\hbox {W}_{0.3}$$ alloys were comprised of the primary phase with FCC structure and the eutectic structures with BCC and FCC phases. The main effect of Al element on $$\hbox {CoCrFeNi}_{2}\hbox {Al}_{1{-}{x}}\hbox {W}_{{x}}$$ alloys was tailoring the proportion of BCC phase and FCC phase, while W element played a greater role than Al element in the solid solution strengthening effect. Hence, the mechanical properties of $$\hbox {AlCoCrFeNi}_{2}$$ alloy can be tailored by adjusting the concentration of Al and W elements to obtain a wider range of applications.