Microstructure evolution and mechanical properties of an annealed dual-phase CrFeCoNiAl0.7 high-entropy alloy

The present work investigated microstructures and mechanical properties of an annealed dual-phase high -entropy alloy (HEA) CrFeCoNiAl0.7 between 700 and 1100 degrees C. It revealed that with the increased annealing temperature, there were rod-like B2 phase precipitating from the FCC-solution matrix, and the orientation between the precipitated B2 phase and the FCC matrix obeyed Kurdjumov-Sachs (K-S) relationship {111}(FCC)// {011}(B2) and <011 >(FCC)//<111 >(B2). The higher annealing temperature resulted in a drastic drop in yield strength, but a significant increase in fracture strain and work-hardening capacity. The positive value of the strain rate sensitivity (SRS) decreased with strain and the SRS of the HEA sample annealed at a lower temperature decreased greatly. Due to the formation of co-clusters, the activation volume of the annealed HEA presented an abnormal trend, that was, it increased with strain.

Automated summary

This study investigated the microstructures and mechanical properties of an annealed dual-phase high-entropy alloy. The results showed that rod-like B2 phase precipitated from the FCC-solution matrix with increased annealing temperature. The higher annealing temperature resulted in a significant decrease in yield strength, but an increase in fracture strain and work-hardening capacity. The activation volume of the annealed HEA exhibited an abnormal trend due to the formation of co-clusters.