|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Deformation and Transitions at Interfaces
||Influence of Dislocation Density on Plastic Deformation near Grain Boundary in Alpha-titanium Studied by Nanoindentations and Modeling
||Yang Su, Philip Eisenlohr, Thomas Bieler, Martin Crimp
|On-Site Speaker (Planned)
To study how pre-existing dislocations affect plastic deformation across grain boundaries, spherical nanoindentations were placed near the same grain boundaries in large-grained alpha titanium following different levels of pre-strain. Prior to nanoindentation, the dislocation distributions, Burgers vectors, and effective densities were characterized using electron channeling contrast imaging and high-resolution electron backscattered diffraction. The plastic deformation and grain boundary strain transfer was evaluated by measuring the nanoindent topography, by atomic force microscopy, as a function of pre-strain. Crystal plasticity finite element simulations of the indentation process were carried out and compared to the experimentally measured indentation topographies. Initial slip resistance and hardening rate parameters were tuned to achieve the best match between simulations and experimental indents at different pre-indentation strain levels, to correlate with the influence of pre-existing dislocations. The role of pre-existing dislocations on both sides of the boundaries was characterized. This work was supported by NSF Grant DMR-1411102.