Abstract Scope |
Nickel (Ni) based alloys are widely used as structural materials in many engineering applications. However, they are susceptible to stress corrosion cracking (SCC) in a corrosive environment and under a tensile load. During SCC, corrosion is found to propagate preferentially along grain boundaries (GBs). As a result, the strengths of the oxidized GBs decrease significantly, leading to brittle intergranular fracture. In this work, density functional theory (DFT) modeling is used to study how the GB oxidation status (from partial to full oxidation), oxygen incorporation type at GBs (interstitial vs. substitutional), GB character, and metal-oxide interface influence the degradation of GB strength, using Ni as a model system. The atomistic modeling results are then used to inform finite-element-method (FEM) based cohesive zone modeling to study how the oxidized GBs impact the intergranular fracture propagation under a tensile load in a polycrystalline Ni. |