Phase transformation-induced strengthening and multistage strain hardening in double-gradient-structured high-entropy alloys

The strengthening and strain hardening behaviors of a CoNiCrFeMn high-entropy alloy were investigated by molecular dynamics (MD) simulation. Two gradient structures, i.e., grain size and composition gradient, were introduced into the alloy, and the alloy is characterized by a high strain hardening rate of 13.84 GPa, the maximum one among reported Cantor-like alloys in MD simulation, within a multistage strain hardening behavior. Distinct phase transformations dependent on the variations of both grain size and stacking fault energy were proposed to play crucial roles in determining the strengthening and the unusual strain hardening behaviors, and the corresponding microstructural evolution at increased strain was provided and discussed.

Automated summary

The strengthening and strain hardening behaviors of a CoNiCrFeMn high-entropy alloy were investigated using molecular dynamics (MD) simulation. Two gradient structures, including grain size and composition gradient, were introduced into the alloy. The alloy exhibited a high strain hardening rate and distinct phase transformations, which were found to play crucial roles in determining the strengthening and unusual strain hardening behaviors. The microstructural evolution at increased strain was also discussed.