  Crystal-level strain rate sensitivity and temperature sensitivity are
investigated in Zircaloy-4 using combined of bending creep test, digital image
correlation, electron backscatter detection and thermo-mechanical tensile tests
with crystal plasticity modelling. Crystal rate-sensitive properties are
extracted from room temperature microscale creep, and temperature sensitivity
from thermal polycrystalline responses. Crystal plasticity results show that
large microscale creep strain is observed near notch tip increased up to 50%
due to cross-slip activation. Grain-level microscale SRS is highly
heterogeneous, and its crystallographic sensitivity is dependent on plastic
deformation rate and underlying grain-based dislocation slip activation.
Pyramidal <c+a> slip and total dislocation pileups contribute to
temperature-sensitive texture effect on yielding and strength hardening. A
faithful reconstruction of polycrystal and accurate rate-sensitive
single-crystal properties are the key to capture multi-scale SRSs.
