Rolling and recrystallization behavior of pure zirconium and zircaloy-4

Résumé

Rolling and recrystallization of pure zirconium and zircaloy-4 have been studied comparatively in this paper.
For the as-received condition, zirconium presented a recrystallized microstructure and the alloy a typical basketweave
microstructure. Comparative rolling tests were performed, and reduction limit curves as a function
of the rolling temperature were determined. At room temperature, pure Zr shows substantial plasticity and the
alloy presents low ductility and many cracks. The ductility of both materials increases significantly with an
increase in rolling temperature at the range between 300 and 500ºC. In static recrystallization studies, samples
of the two materials with similar recrystallized grain size were cold-rolled with a thickness reduction of
55%. During annealing, pure Zr and the alloy soften by recovery and recrystallization, however the relative
contribution of recovery is lesser pronounced in the alloy, for which the recrystallization temperature increases
by about 60°C.
Keywords: Zirconium, zircaloy-4, rolling, recovery, recrystallization.