NSUF 19-1757: Role of Irradiation Damage Cascade Descriptors on ODS and Model ODS Nanocluster Evolution
The objective of this study is to understand the role of irradiation damage cascade parameters on nanocluster evolution in oxide dispersion strengthened (ODS) alloys and their model systems. Nanoclusters play a critical role in the structure-property-performance relationships of advanced nuclear structural and cladding materials such as ODS alloys. However, irradiation can induce coarsening or dissolution of these nanoclusters. These changes can have profound consequences on the structural and mechanical integrity of ODS alloys, and thus there is a critical need to predictably understand the irradiation evolution of nanocluster morphology (i.e. size, number density). Recent work by the co-PI’s team, and funded through several NSUF projects (18-1198, 16-710, 15-569, 15-540, 14-486), has provided significant insight into the effects of irradiation dose, dose rate, and temperature, on oxide nanocluster morphology. Specifically, nanocluster size is controlled by competing mechanisms of recoil dissolution, disordering dissolution, and diffusion-driven growth. Nanocluster number density is less well understood, as it has been found to be relatively insensitive to parameters studied thus far. However, our results from neutron, proton, and Fe2+ irradiations to 3 displacements per atom (dpa) at 500°C on Fe-9%Cr ODS suggest that irradiation damage cascade descriptors (i.e. cascade size and efficiency) could play a critical role in predicting nanocluster number density evolution, warranting further study of cascade effects. We propose to use transmission electron microscopic (TEM) in situ irradiation to rapidly assess the effects of cascade size and efficiency on nanocluster morphology, while gaining insight into the underlying mechanisms of nanocluster number density evolution.
We hypothesize that the irradiation evolution mechanisms of nanocluster number density can be predictably understood by varying irradiation damage cascade size and efficiency. We will substantiate this hypothesis by conducting TEM in situ ion irradiation at the Intermediate Voltage Electron Microscopy (IVEM)-Tandem Facility, using a range of ion energies (50 keV, 500 keV, 1 MeV) and species (H+, Fe+, Au+) to investigate the effects of cascade size and efficiency, respectively. Work will focus on an Fe-9Cr ODS alloy from the same heat that has been studied extensively in our previous NSUF programs. We will also study a binary immiscible Cu-10Ta alloy that is a model for an ODS system. All tests will be carried out at a fixed temperature of 500°C to total dose of 10 dpa, to enable temperature and dose comparisons against our previous NSUF-supported data. Scientifically, this work will fill a critical knowledge gap on the role of cascade size and efficiency on nanocluster morphology. More broadly, these results will inform mechanisms that can be integrated into a comprehensive predictive model of nanocluster irradiation evolution in advanced nuclear alloys. Ultimately, this project will enable intelligent design of irradiation-stable nanoclustered alloys for future nuclear applications.
Additional Info
| Field | Value |
|---|---|
| Abstract | The objective of this study is to understand the role of irradiation damage cascade parameters on nanocluster evolution in oxide dispersion strengthened (ODS) alloys and their model systems. Nanoclusters play a critical role in the structure-property-performance relationships of advanced nuclear structural and cladding materials such as ODS alloys. However, irradiation can induce coarsening or dissolution of these nanoclusters. These changes can have profound consequences on the structural and mechanical integrity of ODS alloys, and thus there is a critical need to predictably understand the irradiation evolution of nanocluster morphology (i.e. size, number density). Recent work by the co-PI’s team, and funded through several NSUF projects (18-1198, 16-710, 15-569, 15-540, 14-486), has provided significant insight into the effects of irradiation dose, dose rate, and temperature, on oxide nanocluster morphology. Specifically, nanocluster size is controlled by competing mechanisms of recoil dissolution, disordering dissolution, and diffusion-driven growth. Nanocluster number density is less well understood, as it has been found to be relatively insensitive to parameters studied thus far. However, our results from neutron, proton, and Fe2+ irradiations to 3 displacements per atom (dpa) at 500°C on Fe-9%Cr ODS suggest that irradiation damage cascade descriptors (i.e. cascade size and efficiency) could play a critical role in predicting nanocluster number density evolution, warranting further study of cascade effects. We propose to use transmission electron microscopic (TEM) in situ irradiation to rapidly assess the effects of cascade size and efficiency on nanocluster morphology, while gaining insight into the underlying mechanisms of nanocluster number density evolution. We hypothesize that the irradiation evolution mechanisms of nanocluster number density can be predictably understood by varying irradiation damage cascade size and efficiency. We will substantiate this hypothesis by conducting TEM in situ ion irradiation at the Intermediate Voltage Electron Microscopy (IVEM)-Tandem Facility, using a range of ion energies (50 keV, 500 keV, 1 MeV) and species (H+, Fe+, Au+) to investigate the effects of cascade size and efficiency, respectively. Work will focus on an Fe-9Cr ODS alloy from the same heat that has been studied extensively in our previous NSUF programs. We will also study a binary immiscible Cu-10Ta alloy that is a model for an ODS system. All tests will be carried out at a fixed temperature of 500°C to total dose of 10 dpa, to enable temperature and dose comparisons against our previous NSUF-supported data. Scientifically, this work will fill a critical knowledge gap on the role of cascade size and efficiency on nanocluster morphology. More broadly, these results will inform mechanisms that can be integrated into a comprehensive predictive model of nanocluster irradiation evolution in advanced nuclear alloys. Ultimately, this project will enable intelligent design of irradiation-stable nanoclustered alloys for future nuclear applications. |
| Award Announced Date | 2019-05-14T15:59:35.947 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Wei-Ying Chen |
| Irradiation Facility | Argonne Tandem Linear Accelerator System |
| PI | Priyam Patki |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 1757 |