Microstructural and mechanical properties of AlCoCrCuFeNiSix (x=0.3 and 0.6) high entropy alloys synthesized by spark plasma sintering

Abstract

This paper explores the impact of Si addition on the microstructural evolution and mechanical properties of AlCoCrCuFeNiSix (x = 0.3 and 0.6 at. ratio) alloys synthesised by spark plasma sintering of mixed powders. X-ray diffraction technique is implemented for phase formation analysis of the present high entropy alloys. The AlCoCrCuFeNi HEA with Si = 0.3 content shows the evolution of duplex phase of FCC and BCC whereas, with further increase in Si = 0.6 content, the sigma phase appeared along with the BCC and FCC phases. Increased hardness and wear resistance with increased Si element can be attributed to the development of the BCC and sigma phase along with solid solution strengthening. As Si has smaller atomic radius contrasted with the other constituent components in the blend, it decreases the mobility of dislocations, increment the strain energy, and consequently improve the solid-solution strengthening effect. (C) 2020 Elsevier B.V. All rights reserved.