An austenitic stainless steel Type 316L weld was thermally aged for 20,000 h at 400 °C and electrochemical characterization was performed to measure corrosion resistance in d–ferrite phase. It is well known that a severe thermal aging causes decrease of fracture resistance and increase of the hardness of d–ferrite, which was related to the spinodal decomposition. After thermal aging, the DL-EPR response of 316L weld was dominated by parent austenite matrix without reactivation peak. To characterize the d–ferrite only, austenite phase was selectively dissolved from the matrix by electrochemical etching method. The double–loop electrochemical potentiokinetic deactivation (DL-EPR) analysis of the d–ferrite phase showed degradation in corrosion resistance after thermal aging with the appearance of a cathodic loop and reactivation peak during the reverse scan. The degradation in corrosion resistance of d–ferrite phase could be attributed to the
localized Cr-depletion due to spinodal decomposition and precipitation of intermetallic phases during thermal aging.
Revised: November 10, 2017 |
Published: January 1, 2018
Citation
Subramanian G.O., S. Hong, H. Lee, B. Kong, K. Lee, T. Byun, and C. Jang. 2018.Electrochemical Characteristics of Delta Ferrite in Thermally Aged Austenitic Stainless Steel Weld. In Proceedings of the 18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems – Water Reactors. (EDM 2017), August 13-17, 2017, Portland, Oregon. The Minerals, Metals & Materials Series, edited by J Jackson, D Paraventi and M Wright, 2, 653-661. Cham:Springer.PNNL-SA-130001.doi:10.1007/978-3-319-68454-3_50