MAE Seminar Series

High-Temperature Tribology of Nickel-Based Superalloys

Ali Beshesti.

Ali Beheshti

Assistant Professor, Department of Mechanical Engineering, George Mason University

November 14, 2024 | 3:30 p.m. | 206 Furnas Hall

Abstract

Operating at high temperatures (HTs) is vital for several types of power and thermal management systems. Perhaps one of the most significant design challenges in contemporary HT systems is maintaining adequate service life and reliability while increasing efficiency. In particular, surface degradation processes involving contact, friction, and wear are of major concern in these applications, given the economic implications resulting from lower efficiency, loss of material, energy consumption, and loss of productivity due to downtime. HT conditions often result in severe surface damage and deformation that degrade performance and eventually cause system failure. My research goal is to uncover and enhance the HT tribo‐contact properties of superalloys. This presentation covers multiple studies on high-temperature tribology and contact behaviors of various nickel-based superalloys at temperatures up to 900 °C. The experiments include both wrought and additively manufactured alloys that are studied through various tribo-contact tests. In addition, I will discuss the application of shot peening and laser peening, including a novel thermally-engineered laser peening process to enhance the microstructural and tribological properties of superalloys, especially at elevated temperatures. The key mechanisms behind the observed enhancements are discussed, and suggestions are made to further improve the effectiveness of laser peening at elevated temperatures.

Bio

Ali Beheshti is an Assistant Professor, Associate Chair for Research, and Director of the Tribology and Surface Mechanics Lab at the Department of Mechanical Engineering, George Mason University. His research focuses on tribology, contact and interfacial mechanics, high-temperature materials, and failure analysis. He also works on advanced manufacturing and surface engineering techniques, such as laser shock peening, to address contact and surface-related failures in harsh environments. Prior to joining George Mason, he was an Assistant Professor at Texas State University-Lamar for two years and a Visiting Assistant Professor at Texas A&M University. He received his Ph.D. in Mechanical Engineering with a minor in Civil and Environmental Engineering from Louisiana State University in December 2013. He serves as Associate Editor for the Journal of Tribology—Transactions of ASME and received the Texas State University Junior Faculty Merit Award in 2017. He has authored or co-authored more than 50 peer-reviewed papers and book chapters in various tribology and mechanical engineering journals.

Event Date: November 14, 2024