Integrating in situ experiment and atomistic modeling to decipher grain boundary deformation mechanisms
Woodruff School of Mechanical Engineering
Georgia Institute of Technology
With recent advances in atomistic modeling and in situ experimental technologies, there have been increased efforts to combine these approaches to understand the atomistic deformation mechanisms at grain boundaries (GBs). Here I will present our recent studies that integrate in situ electron microscopy, nanomechanical testing, and atomistic modeling to investigate GB deformation mechanisms. For example, we have combined in situ high resolution transmission electron microscopy experiments and atomistic simulations to unravel the atomic-scale processes of stress-driven GB sliding and structural transformation that occur unexpectedly at room temperature. We have also combined in situ MEMS-based nanomechanical testing and atomistic reaction pathway simulations to uncover the rate-controlling GB processes that dictate the experimentally measured activation volumes in nanocrystalline metals. The ability to resolve the atomic-scale dynamic processes of GB deformation, through coupled in situ experiment and atomistic modeling, enables a deep understanding of how GBs affect the plastic behavior of polycrystalline materials.