NSUF 21-4245: Comparison of Solute Cluster Formation and Evolution in Neutron-Irradiated ATR-2 to Thermally-Aged Low-Alloy Steels
This proposal focuses on the investigation of neutron-irradiated RPV steels using Atom Probe Tomography (APT). The aim is to utilise access to three steels of different compositions (products of the UCSB ATR-2 experiment; R10, R15, R30) in order to explore the role of Mn, Ni, and Si content on alloy response to irradiation focusing on the formation of Mn-Ni-Si-rich precipitates (MNSPs). Data from all samples will be compared to as-received and thermally-aged alloys of the same compositions
The samples chosen for analysis have been irradiated at a flux of 3.6x10^12 n/cm2s to a fluence of 1.4x10^20 n/cm2 at 290°C. The compositions of the chosen alloys are included in Table 1 within the 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. Use of the FIB will enable sample fabrication for APT. The high spatial and chemical resolution of APT will allow the size, number density, and chemistry of precipitates, mainly MNSPs but also Cu-rich precipitates (CRPs), to be determined. If any dislocations or grain boundaries will be present in the samples, other effects such as segregation of the solute ions will be also detected.
This project aims to enhance the current understanding of RPV alloy irradiation response in relation to composition. In doing so, it would make a significant contribution to the PI’s PhD thesis. The main objectives of these experiments are:
• Investigate chemistry and precipitate size, volume fraction, and composition after irradiation for all 3 alloys using APT (APT samples prepared by FIB-lift-out).
• Study how the variation of Si, Ni, and Mn in the initial composition of the alloys affects the precipitation of MNSPs; a primary interest of the RPV industry.
• Study the roles of high-content solutes in high-Cu alloys and compare it to the behaviour seen in the same alloy that had been subjected only to thermal ageing. Compare MNSPs and CRPs with unirradiated, long-term thermally-aged specimens of the same alloy, in particular R15 which has shown precipitation and unusual hardening behaviour after being thermally-aged for 40,000 hours.
The PI has considerable (~3 years) APT and FIB experience, including site-specific sample preparation. The project is supported by Professor Odette ([email protected]) at UCSB Materials, who has confirmed access to the materials and has been involved with previous RTEs carried out by Oxford Atom Probe Group. Collaborators at UCSB have extensive warm cell experience and will prepare samples for FIB.
Additional Info
| Field | Value |
|---|---|
| Abstract | This proposal focuses on the investigation of neutron-irradiated RPV steels using Atom Probe Tomography (APT). The aim is to utilise access to three steels of different compositions (products of the UCSB ATR-2 experiment; R10, R15, R30) in order to explore the role of Mn, Ni, and Si content on alloy response to irradiation focusing on the formation of Mn-Ni-Si-rich precipitates (MNSPs). Data from all samples will be compared to as-received and thermally-aged alloys of the same compositions The samples chosen for analysis have been irradiated at a flux of 3.6x10^12 n/cm2s to a fluence of 1.4x10^20 n/cm2 at 290°C. The compositions of the chosen alloys are included in Table 1 within the 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. Use of the FIB will enable sample fabrication for APT. The high spatial and chemical resolution of APT will allow the size, number density, and chemistry of precipitates, mainly MNSPs but also Cu-rich precipitates (CRPs), to be determined. If any dislocations or grain boundaries will be present in the samples, other effects such as segregation of the solute ions will be also detected. This project aims to enhance the current understanding of RPV alloy irradiation response in relation to composition. In doing so, it would make a significant contribution to the PI’s PhD thesis. The main objectives of these experiments are: • Investigate chemistry and precipitate size, volume fraction, and composition after irradiation for all 3 alloys using APT (APT samples prepared by FIB-lift-out). • Study how the variation of Si, Ni, and Mn in the initial composition of the alloys affects the precipitation of MNSPs; a primary interest of the RPV industry. • Study the roles of high-content solutes in high-Cu alloys and compare it to the behaviour seen in the same alloy that had been subjected only to thermal ageing. Compare MNSPs and CRPs with unirradiated, long-term thermally-aged specimens of the same alloy, in particular R15 which has shown precipitation and unusual hardening behaviour after being thermally-aged for 40,000 hours. The PI has considerable (~3 years) APT and FIB experience, including site-specific sample preparation. The project is supported by Professor Odette ([email protected]) at UCSB Materials, who has confirmed access to the materials and has been involved with previous RTEs carried out by Oxford Atom Probe Group. Collaborators at UCSB have extensive warm cell experience and will prepare samples for FIB. |
| Award Announced Date | 2021-06-07T15:51:19.513 |
| Awarded Institution | Idaho National Laboratory |
| Facility | Advanced Test Reactor |
| Facility Tech Lead | Alina Zackrone, Yaqiao Wu |
| Irradiation Facility | None |
| PI | Przemyslaw Klups |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 4245 |