Development of a constitutive material model of Mo-Mn-Fe-Co-Ni high entropy alloy through a structured two-phase inverse analysis

High entropy alloys, characterized by their near-equimolar compositions of five or more elements, exhibit unique properties including high strength, thermal stability, and corrosion resistance, making them ideal candidates for demanding applications. Unfortunately, experimental research on their behavior under processing and in-use conditions is expensive and time-consuming. Therefore, the use of computer-aided technology design is required. However, reliable constitutive material models for these alloys are rarely available in the literature. Thus, this research aims to develop a constitutive material model of a Mo-Mn-Fe-Co-Ni high entropy alloy through a structured two-phase inverse analysis. First, a preliminary inverse analysis was conducted to recalculate load-displacement data measured during uniaxial compression tests at varied temperatures and strain rates to the required flow stress data. This first phase helps mitigate the impact of testing artifacts – such as friction and localized heating – that can introduce inhomogeneities in the material and affects the hardening behavior. Then, a full inverse analysis was performed to precisely calibrate the constitutive model parameters, ensuring an accurate representation of the alloy’s flow stress behavior under the tested conditions. This second phase optimizes the model to reflect the material’s inherent properties rather than external test-induced effects, thus improving the robustness and reliability of the flow stress data across a range of loading scenarios. As a result, a reliable form of the constitutive model, along with the identified parameters, was obtained and can be used during computer-aided technology design.