Macroscopic mechanical properties of a polycrystalline metal depend on the microstructure and micromechanical behavior. Studying the evolution and response of polycrystal microstructures under mechanical loading, especially at microstructural interfaces such as grain boundaries and triple junctions, is important to understanding the microstructure property relationship and for process design to generate materials with enhanced properties. This study is a first step in simulating complex microstructural behavior. This talk presented some results of our work in simulating plastic deformation near triple junctions of a polycrystalline metal. This study follows experimental work of M. Li  on a columnar grained pure nickel under 2% tensile strain. A finite deformation based finite element crystal elastic-plastic model is used to simulate the deformation of the microstructure. Elastic deformation is modeled assuming a linear, anisotropic relationship. The plastic deformation considers slip on the slip systems and dislocation entanglement hardening through the Voce-Kocks model. The model is calibrated against macroscale experimental stress-strain observations. Simulation predictions of the dominant slip systems and deformation field are compared to experimental observations.
Acknowledgements: This research is sponsored through a grant from the National Science Foundation, Award CMMI-1729336, DMREF: Adaptive control of Microstructure from the Microscale to the Macroscale.
 M. Li (2018), Deformation at triple junctions: dislocation plasticity and strain distribution, Ph.D. thesis, Rensselaer Polytechnic Institute