Event
MSE Seminar: Dr. William Fahrenholtz, Missouri S&T
Wednesday, November 12, 2025
3:30 p.m.
Room 2108 Chemical and Nuclear Engineering Building
Sherri Tatum
301-405-5240
statum12@umd.edu
Transition Metal Distribution in Dual Phase High Entropy Boride-High Entropy Carbide Ultra-High Temperature Ceramics
Abstract: Transition metal carbides are proposed for use in extreme environments such as those associated with nuclear fission, nuclear fusion, hypersonic flight, and high speed cutting tools. This presentation will focus on the distribution of metals between boride and carbide phases in a dual phase ultra-high temperature ceramics. The model utilized macroscopic thermodynamic principles to predict the distribution of transition metals between boride and carbide phases. An ideal solution model was applied to predict the preference of metals for boride and carbide phases based on the Gibbs’ free energies of formation. Individual metals were analyzed to determine the partitioning between the two phases along with the assumption that metals did not interact with each other. Predicted and actual metal contents showed a strong correlation. Subsequently, results from the model were compared to experimental results, which enabled estimation of the Gibbs’ free energy of formation of phases for which no data were available. The model was extended by supplementing with first-principles calculations to evaluate the role of carbon vacancies in the high entropy carbide on the distribution of vanadium. The model points to future needs for more detailed knowledge of solution thermodynamics in boride and carbide ceramics along with analysis of diffusion behavior in these systems.
Bio: Bill Fahrenholtz is a Curators’ Distinguished Professor of Ceramic Engineering in the Department of Materials Science and Engineering at the Missouri University of Science and Technology. He earned B.S. (1987) and M.S. (1989) degrees in Ceramic Engineering at the University of Illinois at Urbana-Champaign. He completed his Ph.D. at the University of New Mexico in 1992. He has been a Fellow of the American Ceramic Society since 2007 and served as Editor-in-Chief of the Journal of the American Ceramic Society from 2017 to 2023. Bill teaches courses on thermodynamics and technical communication. His current research focuses on the processing and characterization of boride and carbide ceramics. He has published over 260 journal papers and given over 150 invited presentations.
