High temperature deformation behavior of dual-phase Al_0.6CoCrFeNi high-entropy alloys

The deformation behavior of dual-phase (FCC + BCC) Al_0.6CoCrFeNi high-entropy alloy (HEA) was investigated in a temperature range from 900 °C to 1200 °C and a strain rate range from 10⁻³ to 1 s⁻¹. The BCC phase completely recrystallized when the deformation temperature exceeded 1100 °C, while the FCC phase did not even at 1200 °C. Continuing annealing at high temperature with long time (1200 °C for 20 h) can achieve an optimized microstructure, exhibiting that the island-shaped BCC phase uniformly distributed in the FCC phase with a fine equiaxed grain. Compared with the as-cast alloys, the annealed alloy shows an obvious increase in fracture strain with a relatively low decrease in yield stress, demonstrating that such a thermo-mechanical process is feasible for improving the mechanical property of dual-phase HEAs.