Defining recrystallization in pilgered Zircaloy-4: From preferred nucleation to growth inhibition

Pilgered Zircaloy-4 was subjected to recrystallization annealing at 650 °C: temperature sufficient for primary recrystallization but inadequate for noticeable competitive grain coarsening. Associated microstructural developments were monitored through bulk and microtexture measurements. The deformed microstructure had two, generalized, types of grains: fragmenting/deforming and non-fragmenting/non-deforming. The former had higher stored energy of cold work and defined the early recrystallization stages through preferred nucleation. Non-fragmenting grains, on the other hand, did not contribute directly to recrystallization; but provided significant growth inhibition or pinning to the recrystallized grains. A combination of these two mechanisms defined the recrystallization behavior of pilgered Zircaloy-4.