|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Deformation and Transitions at Interfaces
||Investigation of Slip Transfer across Grain Boundaries with Application to Cold Dwell Facet Fatigue
||Zebang Zheng, Daniel Balint, Fionn Dunne
|On-Site Speaker (Planned)
Atomistic simulation is utilised to calculate GB energies with respect to misorientation angles which are then utilised within thermally-activated discrete dislocation plasticity to address slip transfer across GBs in Ti 6242 alloy. It is shown that the stress distribution within the classical dwell fatigue soft-hard grain combination, which is argued to be crucial in facet crack nucleation, changes markedly during the load dwell, leading to much higher basal plane stresses because of stress redistribution, or load shedding. The phenomenon is shown not to diminish when slip penetration is permitted, but in fact, to the contrary, pushes up further the GB stresses within the hard grain. The mechanistic basis of load shedding in titanium alloys is argued to be the time constant associated with thermally activated dislocation escape; the dislocation-grain boundary penetration plays a significant role, but is shown to be less important than the thermal activation processes.