Abstract :
The reaction of zinc vapor with Zircaloy-4 and nuclear grade zirconium was investigated with various analytical techniques: optical metallography, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Based on the results, the Zr-rich part of the Zn-Zr phase diagram was revised. A eutectoid decomposition of ((beta)Zr) occurs at 718 ± 6 °C with a composition of xZr = 0.865; this temperature is lower than the previously accepted 750 °C eutectoid. The solubility of Zn in ( Zr) was determined to be at xZn = 0.0236, a maximum at 725 °C. The intermetallic phase ZnZr2 was observed to occur in samples heat treated at 712 °C and 725 °C, but not in those heat treated at 700 °C and 775 °C.
