Effect of hot-rolling process on the microstructure, mechanical and corrosion behaviors of dual-phase Co-based entropic alloys

Two compositions from dual-phase Co-based entropic alloys with high corrosion resistance were chosen, and the effect of hot-rolling process on the microstrcture, mechanical property and corrosion resistance was investigated in this work. The processing parameters were designed and optimized by CALPHAD calculations. For the case of hot-rolled alloys, fcc + hcp dual-phase structures were confirmed by different characterization techniques, including XRD, ECCI, and EBSD. After testing various mechanical properties and electrochemical corrosion behaviors at room temperature, the hot-rolled alloys exhibit an outstanding mechanical and corrosion resistance property. The hot-rolling process improves the electrochemical corrosion resistance slightly and promotes hardness as well as strength-ductility greatly. The experimental characterizations provide plentiful information about microstructure, crystallographic orientation, lattice misorientation, grain boundaries, and so on. More details for the strengthening and hardening mechanisms could be obtained from the EBSD analysis. The current work shed lights on the design of new alloy recipe as well as the synthesis of novel grade dual-phase entropic alloys with excellent combination of mechanical properties and corrosion resistance which could be applied in harsh environments.