Thursday, June 21, 20182:00 PM - 3:00 PMCNLS Conference Room (TA-3, Bldg 1690)|
Dynamic recrystallization in adiabatic shear banding: an entropic, effective-temperature model
Dynamic recrystallization (DRX) is often observed in conjunction with adiabatic shear banding (ASB) in polycrystalline materials. The recrystallized nanograins in the shear band have few dislocations
compared to the material outside of the shear band. We reformulate the recently developed Langer-Bouchbinder-Lookman (LBL) continuum theory of polycrystalline plasticity and include the creation of grain boundaries. While the shear-banding instability emerges because thermal heating is faster than heat dissipation, recrystallization is interpreted as an
entropic effect arising from the competition between dislocation creation and grain boundary formation. We show that our theory closely
matches recent results in sheared ultrafine-grained titanium. The theory thus provides a thermodynamically consistent way to systematically
describe the formation of shear bands and recrystallized grains therein.
Host: David Metivier