Grain Boundaries: Beauty, Complexity, and Microstructural Mayhem
Speaker
Fadi Abdeljawad
Associate Professor of Materials Science and Engineering, Northwestern University
About This Talk
The properties and functionalities of most engineering materials are shaped not only by the crystals themselves, but also by the defects within them. In the words of Sir F. C. Frank, “Crystals are like people, it is the defects in them that make them interesting.” Among these defects, grain boundaries (GBs) play a particularly important role. Far from being static interfaces, GBs are dynamic entities capable of evolving, transforming, and driving microstructural evolution, thereby profoundly influencing materials properties. In this talk, Northwestern University’s Fadi Abdeljawad will discuss his research group’s recent work exploring the rich dynamics of GBs in extreme environments.
The first part of the talk examines GB structural transformations and their consequences for microstructural evolution. Using large-scale atomistic simulations, Abdeljawad’s group investigates the structural transformation and dynamics of twist GBs in tungsten. The simulations reveal the transformation of a boundary into co-existing GB phases characterized by distinct dislocation networks. These GB phases evolve, with their characteristic length scale increasing over time. The simulations reveal a strong correlation between GB phase evolution and high-temperature boundary dynamics. Abdeljawad will then turn to a GB-driven instability in additively manufactured nano- or micro-lattice architectures. His group demonstrates a morphological instability in which a polycrystalline micro- or nano-rod/ligament breaks up at GBs into an array of isolated domains. GBs play a destabilizing role, with the critical wavelength for the instability decreasing with increasing GB energy. Computational studies predict temporal evolution of interfacial profiles under various temperatures and stress conditions, in quantitative agreement with experimental observations. Together, these studies highlight the rich dynamics of GBs and their ability not only to accommodate microstructural evolution, but to drive it.
About the Speaker
Fadi Abdeljawad is an associate professor in the Department of Materials Science and Engineering at Northwestern University. His research aims to understand how interfaces govern the formation, evolution, and properties of materials microstructures. Abdeljawad obtained his M.A. (2010) and Ph.D. (2014) from Princeton University with a primary focus on theoretical and computational materials science. He subsequently joined Sandia National Laboratories, where he worked in the Computational Materials Department. He then held faculty positions at Clemson (2018–2023) and Lehigh (2023–2026) before joining Northwestern in 2026. His work has been recognized with the Lehigh Outstanding Doctoral Student Advising Award, the TMS Early Career Faculty Fellow Award, the Clemson Junior Researcher of the Year Award, the NSF Junior Faculty Fellowship, and the Army Research Office Young Investigator Program Award.
About the MSE Seminar Series
The Materials Science and Engineering (MSE) Seminar Series features distinguished speakers from leading institutions, offering a platform for sharing groundbreaking research, innovative ideas, and entrepreneurial experiences. Held multiple times each semester, these seminars bring global perspectives world to MIT’s materials research community, exposing students, faculty, and postdocs to cutting-edge concepts and valuable networking opportunities.