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.