A multi-scale constitutive model for analyzing the tensile deformation of eutectic high-entropy alloys

The increase of Al percentage x transforms the crystalline structure of (FeCoNiCrMn)_100-xAl_x high-entropy alloys (HEAs) from single face-centered cubic (FCC) phase to FCC + body-centered cubic (BCC) two phase, which affects subsequent mechanical properties. Therefore, it is necessary to develop a constitutive model that can establish the relationship between microstructure and macro-mechanical properties. In the current study, Mori–Tanaka homogenization method is adopted to describe the evolution of microstructure with increasing Al concentration, which assumes that BCC inhomogeneity is embedded in FCC matrix as a reinforcement phase. A dislocation density-based crystal plasticity theory is employed to simulate the plastic deformation of both FCC and BCC phases. By coupling the influence of Al concentration into the constitutive model, the model is able to predict the plastic deformation of the FCC phase. The multi-scale constitutive theory, implemented into subroutine, is applied to describe the tensile behavior of HEAs. The numerical simulation matches well with the experimental data. The proposed model can accurately predict the tensile deformation of (FeCoNiCrMn)_100-xAl_x HEAs and provide valuable theoretical guidance for optimizing the mechanical performance of HEAs by adjusting the proportion of the components.