Effects of surface deformation on the oxidation behavior of INCONEL 740 superalloy in humid air

Abstract

Effects of surface deformation and grain size on the humid air oxidation of INCONEL 740 have been investigated. Scanning and transmission electron microscopy as well as X-ray spectroscopy are utilized to characterize and quantify the oxides. Results indicate that severe deformation refines surface micrograins to nano-grains, leading to an increase in the mass gain and oxide thickness. Surface deformation prior to oxidation enhances the metal-oxide interface adherence. This enhancement is associated with the mechanical interlocking at the interface which ultimately improves the resistance to exfoliation. The grain size effect on the oxidation of non-deformed samples was found insignificant due to Cr-oxide exfoliation and evaporation. (C) 2016 Elsevier B.V. All rights reserved.