Comments on the Dutton–Puls model: Temperature and yield stress dependences of crack growth rate in zirconium alloys

This work was prompted by the publication of Pulsʹs recent papers claiming that the Dutton–Puls model is valid enough to explain the stress and temperature dependences of the crack growth rate (CGR) in zirconium alloys. The first version of the Dutton–Puls model shows that the CGR has positive dependences on the concentration difference ΔC, hydrogen diffusivity DH, and the yield strength, and a negative dependence on the applied stress intensity factor KI, which is one of its critical defects. Thus, the Dutton–Puls model claiming that the temperature dependence of CGR is determined by DHCH turns out to be incorrect. Given that ΔC is independent of the stress, it is evident that the driving force for DHC is ΔC, not the stress gradient, corroborating the validity of Kimʹs model. Furthermore, the predicted activation energy for CGR in a cold-worked Zr–2.5Nb tube disagrees with the measured one for the Zr–2.5Nb tube, showing that the Dutton–Puls model is too defective to explain the temperature dependence of CGR. It is demonstrated that the revised Dutton–Puls model also cannot explain the yield stress dependence of CGR.