|About this Abstract
|2023 TMS Annual Meeting & Exhibition
|Advanced Characterization of High-temperature Alloys: Phase Evolution during Manufacturing and Service-induced Deformation
|Effect of Temperature, Stress and Environment on Preferential and Internal Oxidation of Ni-base Alloys
|Karen Kruska, Elizabeth J Kautz, Ziqing Zhai, Matthew J Olszta, Daniel K Schreiber
|On-Site Speaker (Planned)
Ni-base alloys are frequently employed in high-temperature applications due to their excellent resistance to corrosion and stress corrosion over a wide range of conditions. With increasing temperature, the oxidation mechanism shifts from passivation to preferential intergranular oxidation to internal oxidation. To assess the effects of temperature (360°C - 800°C), stress and aqueous environment on the degradation of such Ni-base alloys, stressed and unstressed samples were exposed to hydrogenated water and low pO2 gas. Subsequently, the corrosion products were analyzed with scanning electron microscopy, analytical transmission electron microscopy and atom-probe tomography. Low solute alloys that formed passivating oxide films in gas exhibited preferential intergranular oxidation in hydrogenated water. Applied stress alone did not cause passivity break-down under originally passivating conditions. However, enhanced diffusion accelerated oxide penetration in all stressed samples. These distinctions highlight the importance of isolating parameters in the pursuit of a mechanistic understanding of the oxidation behavior in Ni-base alloys.
|Characterization, Copper / Nickel / Cobalt, Nuclear Materials