About this Abstract |
Meeting |
2025 TMS Annual Meeting & Exhibition
|
Symposium
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Chemistry and Physics of Interfaces
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Presentation Title |
Localized Corrosion of Ni-Cr-Fe-Cu Alloys Caused by Cu Segregation-Induced Cr Depletion of Grain Boundaries: Theoretical and Experimental Study |
Author(s) |
Karthikeyan Hariharan, Longsheng Feng, Kamalnath Kadirvel, Vignesh Karunakaran, Koushik Kosanam, Narasi Sridhar, Yunzhi Wang, Gerald S. Frankel, Eric J. Schindelholz |
On-Site Speaker (Planned) |
Karthikeyan Hariharan |
Abstract Scope |
Intergranular corrosion (IGC) in Ni-Cr-Fe alloys is usually caused by grain boundary precipitation of Cr-rich carbides or intermetallic phases. However, this study reports a new mechanism of grain boundary (GB) sensitization without precipitation of Cr-rich phases at GBs in Ni-Cr-Fe-Cu alloys. Depletion of Cr and segregation of Cu to the GBs were observed after thermal aging for 10 h at 700oC, which lies close to the miscibility gap temperature. The depletion of the passivating element Cr at the GBs triggers IGC, as observed through electrochemical, immersion tests and post-mortem morphological characterization. Based on a new thermodynamic model of GB segregation, GB Cu enrichment drives Cr away from the GBs, leading to the subsequent IGC susceptibility. The implications of this new sensitization mechanism on the localized corrosion resistance of Cu-containing commercial Ni-Cr-Fe alloys are discussed. |
Proceedings Inclusion? |
Planned: |
Keywords |
Environmental Effects, |