It is well established that environmentally assisted cracking occucrs in various material and environment
combinations. The cracking can be either "corrosion" based such as those involving anodic dissolution
mechanisms or "fracture" based such as those involving hydrogen embrittlement. For the "fracture"
mechanisms one can consider the theoretical criteria for crack stability based on linear eleastic fracture
mechanics. The criteria can be used to infer the material toughness and the toughness gradient at a
propagating crack tip. These have implications on the mechanisms and kinetics of crack propagation. Of
particular interest is the role that crack geometry may play in crack growth rates and crack stability. The
crack geometry can affect the applied stress intensity factor (KIC) at which catastrophic failure occurs.
This has implications on design and fitness-for-service assessments.