One of the most fundamental problems in materials science is the interaction of dislocations with grain boundaries, as this is necessary to understand plastic deformation, creep, fatigue, fracture, etc. Using Molecular Dynamics, our group simulates dislocations impinging upon and nucleating from various types of grain boundaries, including twins. Many factors affect the result, including type of indicent slip, orientation of system, GB type, stacking fault energy of the material, internal stress state, strain rate, and temperature. In this research, we use a novel technique to measure the activation energy of slip transmission and nucleation as a means to quantify the interaction. Such a process is necessary to understand the complexities of slip-GB interactions and to obtain a means for comparing the energetics of the system during plastic deformation.
Collaborators: Tawhid Ezaz (Intel Corporation), Ian M. Robertson and Huseyin Sehitoglu (University of Illinois, Urbana-Champaign)