Modeling and Analysis of Yielding and Strain Hardening in Metastable High‐Entropy Alloys

Abstract

Metastable dual‐phase high‐entropy alloys (HEAs) have become an attractive paradigm as structural materials due to their outstanding mechanical properties compared with single‐phase HEAs, which originate from the multiple strengthening mechanisms. Herein, a theoretical model is established by integrating the effects of lattice distortion, dislocation, grain boundary, and phase transformation, to study the mechanical responses of metastable HEAs during uniaxial tensile deformation. The results show the contribution of various mechanisms to the strength, and strain hardening can be determined quantitatively. In particular, the face‐centered cubic (FCC) to body‐centered cubic (BCC) phase transformation would dominate the flow stress with plastic strain to exceed 6%, due to the strong phase interface strengthening and the formation of hard BCC phase. This work provides a microstructure‐based constitutive model for predicting the flow stress and strain hardening properties of metastable HEAs.