The oxidation behavior of Zircaloy-4 at 500 .deg. C

The high temperature corrosion tests at 500 .deg. C in 10.3 Mpa steam atmosphere were conducted in order to investigate the effect of microstructural variations on the nodular corrosion resistance of zircaloy-4. Both β-quenched and cold worked alloys displayed good nodular corrosion resistance. Alloys heat treated above recrystallization temperature but in α phase range had accelerated nodular corrosion. For very coarse grained alloys the variation of textures played a major role in providing the necessary nodular corrosion resistance. A qualitative mechanism of nodular corrosion in very coarse grained alloys was proposed