Influence of precipitate density on the nodular corrosion resistance of Zr–Sn–Fe–Cr alloys at 500°C

In a Zr–1.3% Sn base alloy, both the addition of increasing amounts of iron and chromium, conserving a constant Fe/Cr ratio, and the reduction of the cumulative annealing parameter ΣA have beneficial effects on the corrosion resistance in 500°C steam. It is shown that these two observations can be rationalized by considering that the important metallurgical factor is the number of precipitates per unit volume rather than their size.