Constitutive modeling and finite element analysis of metastable medium entropy alloy

In this study, the constitutive model of metastable ferrous Fe60Co15Ni15Cr10 (at%) medium entropy alloy (FeMEA) was constructed based on deformation-induced martensitic transformation (DIMT) behavior under cryogenic temperature. The crystal structure of the FeMEA gradually transformed from a single face-centered cubic (FCC) phase to a body-centered cubic (BCC) phase during deformation. The critical initiation stress criterion and the volumetric fraction evolution model were employed to describe the DIMT kinetics during uniaxial tensile testing. The flow stress model of the FCC phase as a function of the applied strain was developed using the dislocation-based hardening model, and the BCC phase behavior was evaluated based on the macroscopic behavior of the multiphase material and phase transformation kinetics. The decline in the dislocation mean free path for the FCC phase was associated with the grain refinement of the FCC phase due to the transformed BCC islands. To verify its applicability, the model was compared to the experimental data describing phase transformation kinetics and the mechanical behavior.

Automated summary

In this study, a constitutive model for a metastable ferrous medium entropy alloy was developed based on deformation-induced martensitic transformation behavior. The model considered the crystal structure transformation, DIMT kinetics, and the behavior of both the FCC and BCC phases. The model's applicability was verified through comparison with experimental data.