About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
Advances in Materials and Systems for a Hydrogen Economy
|
| Presentation Title |
Imaging the Nanoscale Hydrogen Distribution in an Austenitic Stainless Steel (347H) Using Atom Probe Tomography |
| Author(s) |
Jonathan Poplawsky, Yajie Zhao, Qing-Qiang Ren, Tanzilur Rahman, Geeta Kuari, Yukinori Yamamoto |
| On-Site Speaker (Planned) |
Jonathan Poplawsky |
| Abstract Scope |
Understanding hydrogen trapping due to nano-structural features, such as grain boundaries, precipitates, dislocations, etc., is important for improving the hydrogen embrittlement problem in structural materials. A custom D-charging and custom cryogenic-transfer system was used to detect the nanoscale hydrogen distribution (as D) in cold-rolled and cold-rolled/annealed 347H austenitic stainless steel specimens using atom probe tomography (APT). The results reveal a >10 times higher hydrogen content in the cold-rolled sample (0.197±0.002 at.%) compared to the annealed sample (0.008±0.001 at.%), which possibly reflects the number of vacancies in each sample. In addition, hydrogen was found to segregate to linear dislocation-like features in the cold-rolled specimen and nano-sized NbCN precipitates in the cold-rolled/annealed specimen. Links between density functional theory, dilatometry, and the APT results and how they can be used to understand/improve hydrogen embrittlement will be discussed. APT was conducted at ORNL’s CNMS, which is a U.S. DOE Office of Science user facility. |