Abstract
In LCF-tests the behaviour of protective oxide scales and the first stages of materials damage in the subsurface zone after oxide scale cracking have been investigated. The tests have been performed with Ni 99.2 and Alloy 800 at 300°C and with a 9.5 Cr-steel at 650°C. Concerning oxide scale cracking tensile periods in LCF-deformation are more critical than compressive periods. The strains to scale damage are given in the paper. For Alloy 800 it has been found that the time of preoxidation decides on the beginning of surface crack initiation in the metal. This could be referred to the change of the Cr-content in the subsurface zone due to oxide scale formation and to subsequent Cr-rediffusion from the bulk material. The Cr-content in the subsurface zone decides on whether a protective chromia or a non-protective Fe-rich scale is formed during scale crack healing. For the 9.5 Cr-steel preoxidation and LCF-deformation lead to marked Cr-depletion in the subsurface zone and by this to the formation of non-protective Fe-rich oxide during scale crack healing.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
