Structure and mechanical properties of near-eutectic refractory Al-Cr-Nb-Ti-Zr high entropy alloys

Abstract

In this study, the structure and mechanical properties of the near-eutectic refractory Al₂₄Cr₁₁Nb₁₁Ti₃₇Zr₁₇, Al₂₀Cr₂₀Nb₂₅Ti₂₅Zr₁₁₀, and Al₂₈Cr₁₅Nb₁₅₅Ti₂₀Zr₂₂ (at.%) high entropy alloys were investigated. Both the Al₂₄Cr₁₁₁Nb₁₁Ti₃₇₇Zr₁₇ and Al₂₀Cr₂₀Nb₂₅Ti₂₂₅Zr₁₀₀ alloys had a hypoeutectic structure, while the Al₂₈Cr₁₅Nb₁₅Ti₂₀Zr₂₂ alloy had a hypereutectic one. The proeutectic phase in the Al₂₄Cr₁₁Nb₁₁Ti₃₇Zr₁₇ and Al₂₀Cr₂₀Nb₂₅Ti₂₅Zr₁₀ alloys was the ordered B2 phase and in the Al₂₈Cr₁₅Nb₁₅Ti₂₀Zr₂₂ alloy - the C14 Laves phase. In all three alloys, the eutectic regions possessed a fine lamellar structure composed of a mixture of the C14 Laves and B2 phases. The densities of the alloys were 5.20-5.89 g/cm3