Divergent grain boundary oxidation mechanisms in Inconel 718 with pre-tensile and pre-compressive strain state by bending

Thermo-mechanical coupling during service induces distinct oxidation behavior in Inconel 718 superalloys. This study systematically examines the oxidation response under pre-tension and pre-compression strains, focusing on microstructural evolution and stress-type-dependent mechanisms. Results reveal that tensile strain suppresses oxidation via accelerated Cr outward diffusion forming protective Cr 2 O 3 , which reduces oxidation rate. While compressive strain promotes oxidation through void-enhanced oxygen penetration. These findings provide critical insights for designing oxidation-resistant superalloys under coupled stress environments.