The effect of iodine content and specimen orientation on stress corrosion crack growth rate in Zircaloy-4

The influence of specimen orientation, stress intensity factor (KI), and iodine concentration on the iodine-induced stress corrosion cracking growth rates in Zircaloy-4 was investigated in iodized methanol solutions at ambient temperature. When KI is lower than 20 MPa.m1/2, the intergranular and mixed intergranular/transgranular crack propagation rates increase linearly with (KI - KI,th), KI,th being the onset of propagation stress intensity factor. The increase in iodine content induces an increase of the crack growth rate for a given KI, and a decrease of the KI,th. The specimen orientation is a second order parameter. A crack propagation law, depending on iodine content, is proposed.