Effects of Hydride on Crack Propagation in Zircaloy-4

Abstract

Hydrogen diffuses in the zircaloy-4 fuel clad tube during its service and precipitates as brittle hydride phases beyond terminal solid solubility of precipitation. Brittle hydride precipitates in the region of high stress like crack tips and assists crack propagation leading to failure of the cladding. In order to elucidate the effects of hydride precipitated at the tip of the crack on crack propagation behaviour in zircaloy-4, the numerical simulation is performed on compact tension specimens using the extended finite element method (XFEM) in Abaqus 6.12. An attempt has been made to understand the effects of crack and hydride dimensions on crack propagation by evaluating stress intensity factor and J-integral for different length of crack and hydride. Their values indicate that hydride assists the crack propagation, however, if the length of crack exceeds certain critical length, the effect of hydride precipitation on crack propagation is minimal. The values of stress intensity factor and J-integral are also compared with the experimental values reported in the literature and found to be concordant.