| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Environmentally Assisted Cracking: Theory and Practice
|
| Presentation Title |
Internal Pitting Mechanisms of Chloride-Induced Stress Corrosion Cracking |
| Author(s) |
Janelle P. Wharry, Nathan Gehmlich, Haozheng Qu, Maria A Okuniewski |
| On-Site Speaker (Planned) |
Janelle P. Wharry |
| Abstract Scope |
This talk will illustrate a novel internal pitting mechanism of chloride-induced stress corrosion cracking (CISCC) in 304L stainless steel. In the United States, more than 84,000 metric tons of nuclear waste are held in dry storage canisters made from 304L stainless steel within concrete overpacks. Chloride salt deliquescence onto canisters makes their vertical seam welds susceptible to CISCC. While the transgranular nature of this CISCC is relatively well known, the underlying mechanisms remain poorly understood. Here, we present evidence of a unique internal pitting mechanism in 304L arc welds exposed to boiling MgCl2. The combination of two-dimensional scanning electron microscopy (SEM) and three-dimensional x-ray tomography (XRT) reveals the presence of internal pits and their relationship to cracks. A potential mechanism is proposed in which mechanically-driven crack arrest competes with corrosion-driven pit-to-crack transition to extend cracking. This mechanism is discussed in the context of conventional crack tip blunting theories. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Environmental Effects, Nuclear Materials, Joining |