Application of Computational Modeling and Electron Microscopy in the Exploration and Development of Refractory High Entropy Alloys

The advent of refractory high entropy alloys (RHEA) has afforded the materials community an opportunity regarding the development of new (and improved) high temperature alloys. The problem facing developers of these alloys involves which of the millions of possible RHEAs would present an opportunity for successful alloy development and subsequent application. Thus, there is an absence of a method for choosing potential candidate alloys.

In this presentation, a computational method is described which combines computational thermodynamics and phase field modeling to provide predictions of microstructures and their thermal stabilities and so provide a combinatorial approach to RHEA development. Examples of the use of this computational tool will be given involving the exploitation of alloys in which spinodal decomposition results in combinations of the bcc and B2 phases. Analytical high resolution (scanning) transmission electron microscopy has been used to characterize these microstructures, and nano-indentation has been applied to permit a determination of the deformation mechanisms that occur in both phases and the microstructure in general.