NSUF 11-285: Nanocluster stability of ODS steel under irradiation as determined by atom probe tomography
Ferritic/martensitic (F/M) steels generally provide better swelling resistance under irradiation than austenitic steels, but have poor creep strength at temperatures over 600 °C.[1] Oxide dispersion strengthened (ODS) F/M steels have been developed using the addition of nanoscale Y-Ti-oxide clusters to circumvent the loss of high temperature strength. The clusters act as pinning points for dislocations, improving the high temperature creep strength. [2-4] Additionally, the nanoclusters are expected to promote recombination of irradiationproduced point defects and to trap transmutation-produced He in small, high-pressure bubbles. [5]ODS steels are candidate materials for fission and fusion reactors as cladding and structural components. Since the nanoclusters contribute to the strength of ODS steel, the stability of the nanoclusters under irradiation is an important issue. The overall project objective is to assess the stability of Y-Ti-O nanoclusters under irradiation. The relatively small size of the nanoclusters (2-5 nm) makes analysis difficult, and a multi-faceted approach is necessary for a complete analysis. Energy-filtered transmission electron microscopy (EFTEM) has been successful in imaging the clusters sized as small as 2 nm, while atom probe tomography (APT) is required for imaging clusters smaller than 2 nm.[6] Atom probe tomography is planned to continue at the University of Alabama on a set of previously ion irradiated specimens, but focused ion beam facilities for sample preparation are not readily available through the university. The Idaho National Laboratory (INL) user facility has a FEI Quanta 3 FIB-SEM with two FEI gas injection systems (GIS), one for platinum deposition and another one for C deposition. It also an OmniProbe AutoProbe 200 micro-manipulator. Pt deposition and a micro-manipulator are crucial to the lift-out technique for atom probe samples. It is proposed that atom probe samples be prepared using the INL user facility, and then analyzed at the University of Alabama. These experimental efforts are proposed as an 8 month program.
Additional Info
| Field | Value |
|---|---|
| Abstract | Ferritic/martensitic (F/M) steels generally provide better swelling resistance under irradiation than austenitic steels, but have poor creep strength at temperatures over 600 °C.[1] Oxide dispersion strengthened (ODS) F/M steels have been developed using the addition of nanoscale Y-Ti-oxide clusters to circumvent the loss of high temperature strength. The clusters act as pinning points for dislocations, improving the high temperature creep strength. [2-4] Additionally, the nanoclusters are expected to promote recombination of irradiationproduced point defects and to trap transmutation-produced He in small, high-pressure bubbles. [5]ODS steels are candidate materials for fission and fusion reactors as cladding and structural components. Since the nanoclusters contribute to the strength of ODS steel, the stability of the nanoclusters under irradiation is an important issue. The overall project objective is to assess the stability of Y-Ti-O nanoclusters under irradiation. The relatively small size of the nanoclusters (2-5 nm) makes analysis difficult, and a multi-faceted approach is necessary for a complete analysis. Energy-filtered transmission electron microscopy (EFTEM) has been successful in imaging the clusters sized as small as 2 nm, while atom probe tomography (APT) is required for imaging clusters smaller than 2 nm.[6] Atom probe tomography is planned to continue at the University of Alabama on a set of previously ion irradiated specimens, but focused ion beam facilities for sample preparation are not readily available through the university. The Idaho National Laboratory (INL) user facility has a FEI Quanta 3 FIB-SEM with two FEI gas injection systems (GIS), one for platinum deposition and another one for C deposition. It also an OmniProbe AutoProbe 200 micro-manipulator. Pt deposition and a micro-manipulator are crucial to the lift-out technique for atom probe samples. It is proposed that atom probe samples be prepared using the INL user facility, and then analyzed at the University of Alabama. These experimental efforts are proposed as an 8 month program. |
| Award Announced Date | 2011-02-09T00:00:00 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Yaqiao Wu |
| Irradiation Facility | None |
| PI | Kumar Sridharan |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 285 |