Refractory high entropy alloys (RHEA) also known as multi-principal component alloys (MPCAs) have shown excellent strength and phase stability at elevated temperatures, making them potential candidates for demanding engineering applications. Tailoring of such alloys is very demanding due to vast design space. Furthermore, understanding the process-structure-properties-performance relationships of the manufactured alloys is challenging due to uncertainties related to solidification kinetics and microstructural heterogeneities affecting mechanical properties of the materials.

This work focuses on demonstrating an application of crystal plasticity (CP) approach to analyse  RHEA mechanical response at the level of single crystals containing solute segregation (e.g., dentritic structures) and at the polycrystal level. Analytical solid solution strengthening models to predict the yield strength of the material based on misfit volumes and elastic constants of elements in material can be used as first indicators of the material properties. However, to further link solid solution strengthening effects with the prevailing microstructure in terms of structure-property relationships, we will develop a new CP model incorporating this effect on deformation mechanisms . Characterization data, such as SEM-EDS maps, are utilized to formulate intra-grain heterogeneities explicitly involved in the computational domain and providing segregation dependent material parameters for the model.

Polycrystalline microstructures are analysed by employing both detailed segregation containing grains and homogenized grains to evaluate the effectiveness of the microstructural characteristics. Stress/strain localization of the microstructures and their characteristics are analysed, which are eventually responsible for the strength/damage of the material. The model responses are compared with experimental uniaxial compression data, including elevated temperatures. In addition, the results are used to shed light on the reasons behind excellent mechanical properties of the selected/designed alloys. Finally, it is clear that the crystal plasticity approach is a crucial part of the multi-scale modelling framework, including atomistic modelling tools and phase field solidification kinetics/cellular automata crystallization tools.