Role of twinning in the hardening response of zirconium during temperature reloads

We aim to elucidate the interaction between twinning and slip in clock-rolled zirconium plate, and the role that it plays in the hardening response. Compression samples were deformed at liquid nitrogen temperature along the through-thickness and the in-plane direction of the plate to create compressive or tensile twins, respectively. The same samples were reloaded at room temperature and large differences in stress–strain response were observed with respect to samples loaded at room temperature from the beginning. Mechanical tests were complemented with texture analysis by neutron diffraction and orientation imaging microscopy, and also by polycrystal modeling. We show that twins influence the reload behavior by either reorienting material for easy slip or by providing barriers to slip.