Interaction of stress corrosion cracks in single crystals Ni-Base superalloys

•A Phase field model has been used to understand the role of crack interaction on predicting the life of nickel components.•The time and stress dependent nature of stress corrosion cracking has been highlighted.•Critical crack spacings and distributions of cracks needed to encourage or prevent crack interactions has been established.•For a given density of cracks, a local reduction in crack tip stresses is seen, as such reducing the driving force for SCC. Stress corrosion cracking (SCC) can be detrimental to nickel-based superalloy components exposed to harsh environments in aero-gas turbines. During flight, engines consume contaminants deposited on the surface of a blade, often leading to degradation. Cracking can initiate within minutes and rapidly propagate, depending on the temperature, contaminants, and applied stress. This study investigated the interaction between cracks in single-crystal turbine blades at intermediate temperatures by integrating experimental and computational methods. We performed C-Ring tests to quantify the time required for cracking, along with microscopic characterisation of the damage. In parallel, we developed a finite-element simulation for C-Ring tests using a phase field model calibrated to match the location of the cracks. The results demonstrated that the crack's characteristic spacing and length determine the likelihood of shielding or coalescing mechanisms.