The texture dependence of KIH in Zr–2.5%Nb pressure tube materials

The effects of the texture on the threshold stress intensity factor for a delayed hydride cracking (DHC: KIH) along the radial direction was investigated for Zr–2.5%Nb CANDU pressure tube materials. The KIH of the specimen with the highest basal pole component (F) for the cracking plane appeared to be the lowest KIH, ∼9 MPa √m, whereas that with the lowest F was over 20 MPa √m. The KIH at 250 °C decreased linearly with F for the cracking plane. The texture dependence of KIH on F was compared with the results from the literature, and the comparison appeared to be consistent. This dependence of KIH can be explained by the rule of a mixture, as proposed in a previous work. It is concluded that the KIH is predominantly determined by the F for the cracking plane and it is subsequently affected by the cracking direction. Why the texture dependence of KIH in the radial direction occurs is discussed.