Effect of Hydrogen and Hydride on Fatigue Cracking Rate of Zirconium-Based Alloys and Its Estimation

In this paper, compact toughness samples are used to study the fatigue cracking prolongation behaviors of Zr-4 and Zr-Sn-Nb alloys with different hydrogen contents. Test results indicate that the hydro- gen contents have little effect on the fatigue cracking rate, and fracture behavior is controlled by the nature fatigue cracking mechanism, which include crack budding, stable prolonging and rapid ultimate fracture. According to the mechanism of fatigue cracking, the relationship of fatigue cracking rate （da/dN） and general properties of materials has been induced. In term of this relationship, calculating values of fatigue crack rate of zirconium-based alloys are consonant with the experimental values.