Stress Corrosion Cracking of Zirconium in Nitric Acid

The stress corrosion cracking (SCC) of zirconium in HNO₃ has been investigated by slow strain rate and constant strain techniques. Zirconium was found to be susceptible to SCC at concentrations of 20 Wt% or greater. Cracking was observed over a wide potential range, from 0.6 to 1.15 V(SCE) at 25 C; the free corrosion potential was approximately 1.08 V(SCE). The failure was transgranular, cleavage-like, and similar to that observed in zirconium in other environments. Aspects of the fractography and potential dependence are generally not consistent with a hydrogen model for cracking.