NSUF 25-5414: Real-time TEM observation of cavity evolution with helium implantation and nanomechanical loading in Fe and Ni based alloys
Fe-Cr based ferritic steels and nickel alloys are used extensively in nuclear reactor applications. High temperature helium embrittlement limits their use in nuclear reactor cores and poses a significant threat to the stability of structural materials. The embrittlement can be much more severe when stress is applied during irradiation. Dislocations generated by plastic deformation (thermal creep conditions) may offer a fast diffusion path for transport of helium atoms to grain boundaries. The proposal aims to study how applied stress, pre-existing dislocation density, and Cr atoms affect cavity formation and migration in the matrix of Fe-based or Ni-based alloys at elevated temperature under He ion irradiation. We propose to perform in-situ helium irradiation combined with nanomechanical loading to pure Fe, Fe-8Cr, and Ni-20Cr alloys using the Intermediate Voltage Electron Microscopy (IVEM) facility at Argonne National Laboratory (ANL). The in-situ ion irradiation with 0 or up to 5% strain deformation will be conducted under 15 keV helium ions at 400 ºC with the dose rate 4E11 ions/cm-2/s up to 1 hour. The real time evolution of helium cavities in matrix will be recorded by installed camera in IVEM facility at ANL and analyzed by machine learning later at University of Tennessee. The research will provide insights into understanding the mechanism of helium embrittlement under extreme conditions in nuclear reactors.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | University of Tennessee-Knoxville |
| DOI | 10.46936/NSUF/60015381 |
| Embargo End Date | 2027-09-03 |
| Facility Tech Lead | Wei-Ying Chen |
| Irradiation Facilities | Intermediate Voltage Electron Microscopy (IVEM)-Tandem Facility |
| NSUF Call | FY 2025 RTE 2nd Call |
| PI | Siwei Chen |
| PIE Facilities | Intermediate Voltage Electron Microscopy (IVEM)-Tandem Facility |
| Project Member | Dr. Siwei Chen, Post-doc - University of Tennessee-Knoxville |
| Project Type | RTE |