NSF EPSCoR Research Fellows: NSF: Dynamic Response Characterization of High Entropy Alloys under High-Velocity Impact Conditions

The overarching goal of this two-year project is to advance the understanding and design of resilient high entropy alloys (HEAs) capable of effectively mitigating extremely high velocity impact loads. Such impacts are prevalent in critical applications ranging from projectiles striking land vehicles to supersonic aircraft navigating through dusty atmospheres. Despite extensive research efforts aimed at comprehending the underlying dynamic failure mechanisms, there remain notable issues such as the exploration of microstructure-property-performance relationships in HEAs and the design of new HEAs tailored for high velocity impact scenarios. To address these challenges, we will collaborate with Dr. Kaliat (K.T.) Ramesh''''s research group at Johns Hopkins University (JHU), leveraging their cutting-edge facilities not available at our home institution. Our project unfolds in three key phases. Initially, we will conduct high/hyper-velocity impact experiments at velocities ranging from 1 km/s to 3 km/s, utilizing JHU''''s Hypervelocity Facility for Impact Research (HyFIRE). This phase promises invaluable insights into HEAs'''' performance under high-speed impacts. Subsequently, the second phase focuses on characterizing the dynamic mechanical properties of HEAs at medium to high strain rates (up to 103 s-1), utilizing JHU''''s Kolsky Bar Facility. This will shed light on how deformation mechanisms, flow stress, and strain- hardening are influenced by strain rate. Finally, in the third phase, we will thoroughly characterize the microstructures of HEAs before and after the aforementioned testing, elucidating the microstructure-property-performance relationships. The outcome of this project will pave the way for development of high-performance HEAs for high/hyper-velocity impact applications by appropriate microstructural design.