"Advanced Characterization-Guided Design and Evaluation of Refractory High-Entropy Alloys for Extreme Environments"

This event is sponsored by FAMU-FSU Engineering Department of Mechanical and Aerospace Engineering.

Abstract: State-of-the-art characterization techniques play a critical role in uncovering the microstructural origins of materials’ macroscopic properties. In this presentation, I will highlight how a suite of advanced analytical tools—including scanning transmission electron microscopy (STEM), electron energy-loss spectroscopy (EELS), transmission Kikuchi diffraction (TKD), electron backscatter diffraction (EBSD), atom probe tomography (APT), focused ion beam (FIB) 3D tomography, nanoindentation, and thermodynamic modelling—can be employed to design, evaluate, and improve new materials such as refractory high-entropy alloys (RHEAs). RHEAs, composed of multiple principal elements, exhibit remarkable potential for applications under extreme environments. Through integrated structural and chemical analyses, we demonstrate how compositional tuning, heat treatment, and impurity control influence phase stability, mechanical behavior, and oxidation resistance. Notably, trace impurities such as oxygen and nitrogen, while initially enhancing solid-solution strengthening, was observed to promote phase segregation during long time thermal aging, leading to gradual softening as these interstitials deplete from the matrix.

Junliang Liu, Ph.D.

Assistant Professor

Materials Science and Engineering

FAMU-FSU College of Engineering

Speaker Bio: Dr. Junliang Liu is an Assistant Professor in Materials Science and Engineering at the FAMU-FSU College of Engineering. He completed his DPhil in Materials and postdoctoral training at the University of Oxford, followed by a staff scientist position in the Department of Nuclear Engineering & Engineering Physics at the University of Wisconsin–Madison. At FSU, he leads the Materials for Fusion and Fission Energy (MFFE) group, which uses advanced electron microscopy to study the microstructural evolution of materials under nuclear reactor conditions, with the broader goal of developing better materials that make nuclear power cheaper and safer.