Multi-Scale Investigation of Oxygen-Induced Damage in Nickel-Based Superalloy Alloy 718

Understanding damage mechanisms across scales is crucial to ensure the structural integrity of nickel-based superalloy components under demanding conditions. This study highlights key aspects of a multi-scale experimental approach for analyzing oxygen-induced cracking in Alloy 718. Microcantilever bending tests on specific grain boundaries were combined with corrosion tests and detailed analyses using high-resolution scanning electron microscopy, electron backscatter diffraction, and energy-dispersive X-ray spectroscopy. The results suggest that susceptibility to oxidative attack is significantly impacted by the type of grain boundary, emphasising the importance of local crystallography in oxygen diffusion and elemental redistribution. By bridging local microstructural features with global mechanical response, the presented multi-scale approach allows the parameterization of physically based material models and identifies grain boundary engineering as a promising strategy for improving damage tolerance.