ERI: Comparative Mechanisms of Dynamic Strain Aging in Face-Centered Cubic (FCC) and Body-Centered Cubic (BCC) Metals

Understanding how metals deform under varying temperatures and loading conditions is essential to advancing the engineering of materials used in critical infrastructure, transportation, and energy systems. One important phenomenon influencing the reliability of structural materials is dynamic strain aging, which arises from interactions between moving crystal defects and diffusing atoms, often leading to unstable deformation and reduced ductility. Despite extensive prior research, the mechanisms governing dynamic strain aging remain incompletely understood, particularly across materials with different crystal structures. This Engineering Research Initiation (ERI) project seeks to establish a fundamental understanding of how crystal structure affects dynamic strain aging and the resulting mechanical response. The research will advance the engineering design of materials with improved reliability and performance in demanding environments. In addition to advancing fundamental knowledge, the project will contribute to national priorities by enabling safer and more efficient engineering systems. It will also support the education and training of undergraduate and graduate students in mechanics of materials, integrating computational modeling with experimental analysis, and will include outreach activities in science and engineering. The objective of this project is to develop a mechanism-based constitutive modeling framework to describe deformation instabilities associated with dynamic strain aging in metallic systems with different crystal structures. The research will combine experimental data analysis, atomistic simulations, and continuum modeling to quantify key physical parameters, including solute diffusion rates, dislocation–solute interaction energies, and temperature-dependent dislocation mobility. The framework will explicitly account for differences in dislocation behavior across crystal structures, such as edge-dominated motion in face-centered cubic systems and temperature-dependent screw dislocation motion in body-centered cubic systems. Model predictions will be calibrated and validated against mechanical testing data across a range of temperatures and strain rates, including measurements of strain rate sensitivity and deformation instabilities. By establishing a unified and predictive modeling framework, this work will provide new insights into the role of crystal structure in dynamic strain aging and support the engineering of more reliable metallic materials for advanced applications. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2553204 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Yooseob Song | Institution: University of Alabama in Huntsville, HUNTSVILLE, AL | Award Amount: $200,000 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2553204 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2553204.html