NSUF 26-5633: Exploring Irradiation Effects on Laser Powder Bed Fusion Produced Stainless Steel 316L
Localized stresses are known to have a profound effect on the mechanical properties of structural materials. When irradiated, these residual stresses may become even more complex as induced defects begin to interact with the pre-existing microstructure. Additionally, the laser powder bed fusion additive manufacturing process has the tendency to create a sparse network of porosity which can exacerbate the degradation of mechanical properties when irradiated. We hypothesize that the stress state, and by extension the mechanical performance of LPBF structural materials, is primarily affected by the unique microstructure developed during the manufacturing process and subsequent evolution during irradiation in a prototypic reactor environments. Relatively limited data on the mechanical properties of neutron irradiated AM LPBF material exists, and of the data available there are clear examples of that material behaving in a way that is very different from traditionally wrought material. ASTM standard compact-tension (CT) specimens tested in simulated Normal Water Chemistry (NWC) and Hydrogen Water Chemistry (HWC) exhibited dramatic off-plane cracking during traditional crack growth rate (CGR) testing, even though the material had undergone a solution annealing thermal treatment meant to homogenize the microstructure to eliminate residual stresses within the material, and therefore this type atypical cracking behavior. We hypothesize internal stresses may have redirected the cracking, through a combination of those which existed based on the AM microstructure prior to irradiation as well as additional changes which were induced through neutron bombardment. By utilizing X-ray diffraction, we can characterize the residual stress state in both the non-irradiated and irradiated sample to discern radiation-induced stress. Meanwhile, X-ray CT will enable 3D visualization of the crack path as well as the porosity, allowing us to correlate porosity to stress and crack propagation. This work will will provide evidence for or against the suitability of LPBF-fabricated stainless steels for nuclear applications.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | Idaho National Laboratory |
| DOI | 10.46936/NSUF/60017668 |
| Embargo End Date | 2028-04-22 |
| Facility Tech Lead | Noé Morales |
| NSUF Call | FY 2026 RTE 1st Call |
| PI | William Chuirazzi |
| PIE Facilities | Irradiated Materials Characterization Laboratory |
| Project Member | Dr. Drew Johnson, Post Doctoral Research Associate - Idaho National Laboratory (https://orcid.org/0000-0002-7996-4691) |
| Project Member | Dr. William Chuirazzi, Micro X-ray Computed Tomography Instrument Scientist, Diffraction and Imaging Group Lead - Idaho National Laboratory (https://orcid.org/0000-0003-2193-0744) |
| Project Member | Dr. Brian Newell, X-Ray and Neutron Diffraction Materials Scientist - Idaho National Laboratory (https://orcid.org/0000-0002-6310-1242) |
| Project Type | RTE |
| Sample Identifiers | 10285,10289,12768 |