Microstructure characterization and phase evolution of equiatomic AlCoMoFeNi high entropy alloy synthesized by mechanical alloying

Abstract

The present study deals with the fabrication of a novel AlCoMoFeNi high-entropy (HEA) alloy using mechanical alloying techniques. The developed HEA was characterized by X-ray diffraction, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) equipped with energy dispersive x-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The crystallite size of the high-entropy alloy solid solution was determined to be 20 ± 1 nm, with a lattice strain of 0.467 ± 0.03 % and a lattice parameter of 3.98 ± 0.08 Å. A number of characteristics, including melting point, mixing enthalpy change, mixing entropy change, atomic size difference, electronegativity difference, and valence electron concentration, were computed in order to ascertain the conditions regulating the formation of high-entropy alloys. A HEA with BCC and FCC solid solution was obtained after mechanical alloying, which was confirmed by experimental findings as well as thermodynamic calculations.