Microstructure and Properties of Multi-Component Al<sub>x</sub>CoCrFeNiTi<sub>0.5</sub> High-Entropy Alloys

Abstract

The multi-component AlxCoCrFeNiTi0.5 (x=0, 0.2, 0.5, 0.8, 1.0) high-entropy alloys were prepared by vacuum arc melting. The microstructure and mechanical properties were studied. It was found that the structure transformed from FCC into FCC + BCC + Laves, and finally into BCC with the increase of Al content. The compress test results showed that with the addition of aluminium from 0 to 1.0, the fraction strength increased while plasticity reduced. In the stain rates of 5×10 -3 /s and 1×10 -3 /s, when x=0.8 the fraction strength achieved maximum and x=0 the plastic was best, the strength of 2879MPa and 2433MPa, the strain of 0.21 and 0.22, respectively. The hardness increased obviously (from Hv479.1 to Hv692.7) when Bcc phase and Laves phase appeared. The analysis revealed that the strengthen mechanism was mainly composed of solid solution strengthening and precipitation strengthening.