Effects of hydrogen and specimen thickness on plane-stress fracture toughness, Jc, and J-R curve of Zircaloy-4 plates were investigated, using compact tension specimens. Crack growth increments were measured by the single specimen unloading compliance method.
Within the limits of this study (0.75-1.95 mm), the effect of specimen thickness was found negligible on Jc and J-R curve, while the tearing modulus, Tm, was slightly increased with the increase of thickness.
The contents of hydrogen were found to have a definite embrittling influence resulting in lowering the value Jc and Tm and J-R curve.
