On the Optimization of the Microstructure and Mechanical Properties of Al-Co-Cr-Cu-Fe-Ni-Ti –Based High Entropy Alloys

Abstract

Widely investigated AlCoCrCuFeNi high entropy alloy has been chosen for optimization of the microstructural and mechanical properties. Different paths have been chosen for optimization; namely the decrease of segregating element Cu, the increase of oxidation protective elements Al and Cr and the approach towards a γ-γ' microstructure as in Ni-based superalloys. Microscopical observation has been made for each optimization step and compared with results obtained by Vickers microhardness measurements. Out of five derivate alloys: AlCoCrFeNi, Al₂₃Co₁₅Cr₂₃Cu₈Fe₁₅Ni₁₆, Al₈Co₁₇Cr₁₇Cu₈Fe₁₇Ni₃₃, Al₈Co₁₇Cr₁₄Cu₈Fe₁₇Ni₃₃Mo₁Ti₁W₁ and Al₁₀Co₂₅Cr₈Fe₁₅Ni₃₆Ti₆, the most promising one has been chosen for further investigation.

Keywords: High entropy alloys; Microstructure; Transmission electron microscopy.