ICME-Guided Alternative Fabrication Pathway for Refractory High Entropy Alloys

Refractory High-Entropy Alloys (RHEAs) have great potential to be the next-generation material of choice for high-temperature applications, such as in Navy’s gas turbine engines, due to their superior strength at high temperature beyond the application range of superalloys. However, processing these alloys are difficult due to their disparate and very high melting points of the constituent elements.  Elemental partitioning into phases during solidification promotes non-uniform properties. The elemental non-uniformity leads to potentially deleterious effects on the high-temperature oxidation resistance of the material.  The Phase I of this STTR therefore aims at ICME-guided process design to reduce element partitioning.  CFD Research has partnered with Applied Research Laboratory at Penn State University to apply thermodynamics, solidification simulation, and machine learning to design process conditions below the melting points of the constituents using metal oxides as feedstock with a goal to avoid element partitioning.  This ICME-guided process conditions will be applied to process a RHEA using Field Assisted Sintering Technology.  Various non-destructive imaging techniques will be used to characterize the microstructure and elemental homogeneity. The ICME-guided process design will then be validated, and scope of improvements will be documented.  In Phase II, the models will be improved and improved ICME tools will be used for process optimization and variation of mechanical properties on process conditions will be predicted.