Modeling the influence of crack path deviations on the propagation of stress corrosion cracks

Stress corrosion cracks typically nucleate at a stress concentration in the surface and propagate away from the surface on a plane perpendicular to the applied stress. While this is a good macroscopic description of crack propagation, on a microscopic scale, crack tips regularly deviate from this ideal orientation due to deviations in the preferred microstructural paths for crack propagation and microstructural obstacles. These crack path deviations can be influenced by grain boundary size, shape, and crystallographic texture and may or may not have a significant influence on the accuracy of crack propagation rate measurements or the predictions of propagation rate models. This paper examines the effects that crack path deviations can have on measuring and modeling stress corrosion crack propagation by developing a technique for quantifying these deviations and estimating the difference between the measured and the true rate of crack tip propagation.