Dynamic Recrystallization in Zircaloy-2

Presented here is the evolution of dynamic recrystallization (DRX) with strain in Zircaloy-2 deformed at 800 °C and 10 –1 s −1 . The flow stress showed a peak followed by softening to steady state. Specimens were deformed to predetermined strains and their microstructure was characterized using electron back scatter diffraction. DRX grains were identified using the criteria of grain orientation spread. The grain size decreased with strain up to a strain of 0.6, beyond which grain size distribution remained very similar. From grain reference orientation deviation and kernel average misorientation maps, it was seen that grain boundaries move into regions of higher dislocation density, suggesting that during hot deformation, Zircaloy-2 underwent discontinuous dynamic recrystallization. Compared to hot deformed Zr, it was observed that the final grain size of Zircaloy-2 was smaller. The final texture showed the basal poles to be aligned nearly parallel to the compression axis.