NSUF 17-1016: Site-specific Atom Probe Tomography Characterisation of Grain Boundaries in Archival Surveillance Steels From Advanced Test Reactor (ATR-2) Neutron Irradiation Experiment
This proposal focuses on the site-specific characterisation, via atom probe tomography (APT), of grain boundaries in a complimentary set of neutron-irradiated alloys. These steels have been irradiated to a fluence of 1.4E20 n/cm2 at 290°C and a flux of 3.6E12 n/cm2s in the UCSB ATR-2 experiment. The compositions of these alloys are included in Table 1 of the attached proposal narrative.
All essential equipment is available at INL CAES Microscopy and Characterization Suite (MaCS); this includes a dual-beam FIB and LEAP 4000X HR. The combined use of these instruments will allow grain boundaries from each alloy to be prepared for APT analysis. The high spatial and chemical resolution of APT will allow the size, number density, and chemistry of precipitates to be determined and permit characterisation of grain boundary chemistry.
The application of APT to analyse the grain boundary chemistry, and in particular to investigate the precipitation of deleterious phases at these sites, will be combined with existing experimental characterisation of irradiation-induced changes to mechanical properties in these alloys. This will provide new insights into the correlation between microstructural damage and the resulting changes in mechanical properties as a result of in-service exposure to irradiation.
This work aims to support the Light Water Reactor Sustainability Program (LWRSP) RPV task and will also make a significant contribution to the PI’s PhD thesis. The main objectives of this experiment are: • Undertake FIB-based site-specific specimen preparation to precisely incorporate grain boundaries into a series of APT specimens for each alloy • Perform atom probe analyses of grain boundaries in each of the five individual irradiated alloys • Investigate grain boundary chemistry and precipitate size, volume fraction, and composition after irradiation • Compare these results to as-received materials and to specimens which have undergone long-term thermal-ageing (up to 20,000 hours) • Establish further insight into the thermodynamics of Mn-Ni-Si-rich precipitate formation
The PI has considerable APT experience, including site-specific sample preparation using FIB. Collaborators at UCSB have extensive warm cell experience and will conduct FIB sample preparation. The experimental objectives will be achieved within six months of the date of the award and data analysis will be performed over the next few months with assistance from collaborators at UCSB.
Additional Info
| Field | Value |
|---|---|
| Abstract | This proposal focuses on the site-specific characterisation, via atom probe tomography (APT), of grain boundaries in a complimentary set of neutron-irradiated alloys. These steels have been irradiated to a fluence of 1.4E20 n/cm2 at 290°C and a flux of 3.6E12 n/cm2s in the UCSB ATR-2 experiment. The compositions of these alloys are included in Table 1 of the attached proposal narrative. All essential equipment is available at INL CAES Microscopy and Characterization Suite (MaCS); this includes a dual-beam FIB and LEAP 4000X HR. The combined use of these instruments will allow grain boundaries from each alloy to be prepared for APT analysis. The high spatial and chemical resolution of APT will allow the size, number density, and chemistry of precipitates to be determined and permit characterisation of grain boundary chemistry. The application of APT to analyse the grain boundary chemistry, and in particular to investigate the precipitation of deleterious phases at these sites, will be combined with existing experimental characterisation of irradiation-induced changes to mechanical properties in these alloys. This will provide new insights into the correlation between microstructural damage and the resulting changes in mechanical properties as a result of in-service exposure to irradiation. This work aims to support the Light Water Reactor Sustainability Program (LWRSP) RPV task and will also make a significant contribution to the PI’s PhD thesis. The main objectives of this experiment are: • Undertake FIB-based site-specific specimen preparation to precisely incorporate grain boundaries into a series of APT specimens for each alloy • Perform atom probe analyses of grain boundaries in each of the five individual irradiated alloys • Investigate grain boundary chemistry and precipitate size, volume fraction, and composition after irradiation • Compare these results to as-received materials and to specimens which have undergone long-term thermal-ageing (up to 20,000 hours) • Establish further insight into the thermodynamics of Mn-Ni-Si-rich precipitate formation The PI has considerable APT experience, including site-specific sample preparation using FIB. Collaborators at UCSB have extensive warm cell experience and will conduct FIB sample preparation. The experimental objectives will be achieved within six months of the date of the award and data analysis will be performed over the next few months with assistance from collaborators at UCSB. |
| Award Announced Date | 2017-09-20T12:30:52.117 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Yaqiao Wu |
| Irradiation Facility | None |
| PI | Benjamin Jenkins |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 1016 |