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: K-IH) along the radial direction was investigated for Zr-2.5%Nb CANDU pressure tube materials. The Kill of the specimen with the highest basal pole component (F) for the cracking plane appeared to be the lowest K-IH, similar to 9 MPa root m, whereas that with the lowest F was over 20 MPa root m. The K-IH at 250 degrees C decreased linearly with F for the cracking plane. The texture dependence of K-IH on F was compared with the results from the literature, and the comparison appeared to be consistent. This dependence of K-IH can be explained by the rule of a mixture, as proposed in a previous work. It is concluded that the K-IH is predominantly determined by the F for the cracking plane and it is subsequently affected by the cracking direction. Why the texture dependence of K-IH in the radial direction occurs is discussed. (c) 2005 Elsevier B.V. All rights reserved.