Effects of texture on KIH in the radial direction in Zr-2.5%Nb pressure tube materials

The texture dependence of KIH in the radial direction was investigated in Zr-2.5%Nb pressure tube materials for CANDU reactor. The flat cantilever beam specimens were machined and taken at various angles to the longitudinal direction from the flattened pressure tube material and the textures of the cracking planes were varied in the cantilever specimens. The results show that the KIH values decrease linearly at 250°C to the amount of an increase in the basal pole components in the cracking plane. The KIH in the transverse direction specimen has the maximum basal pole component and has the minimum, 9 MPa√m. The texture dependence of KIH explained by the rule of mixture using the basal pole component (F) and a fraction of the ductile matrix (1-F). Rationale for the differences in KIH between the cantilever beam (CB) and the compact tension (CT) specimens is proposed.