NSUF 13-398: Study of Interfacial Interactions using Thin Film Surface Modification: Radiation and Oxidation Effects in Materials
Oxide dispersed Strengthen (ODS) steels exhibit an improved response to radiation damage as compared to conventional ferritic and austenitic steels. The stability of the fine dispersion of nanoparticle in the matrix is critical for the application of these steels in new generation nuclear power plants. The interface between the clusters and the matrix, in the steel, plays a key role in dictating its long-term stability under the influence of radiation and high temperatures. To gain a better understanding to the role of interfaces, we are depositing thin films (~ 350 nm in thickness) of yttrium, yttrium oxide, titanium and titanium oxide on substrates of Fe-12%Cr pure binary alloy substrates followed by elevated temperature ion irradiation (with nickel ions). A fundamental understanding of interfacial effects (stability of interfaces under radiation at elevated temperatures, film substrate interface mixing, evolution of defects and other phases at the interface), is crucially important for the development of materials suitable for the extreme environments of a nuclear reactor. Transmission Electron Microscopy (TEM) and Scanning-TEM (STEM) coupled with Energy Dispersive Electron Spectroscopy (EDS) will be used to investigate physical and chemical stability of the interface between the thin films and the substrate on a nanometer scale after radiation at high temperature. In the proposed research, the experimental work will be also integrated with multi-scale computational modeling (molecular and particle dynamics codes), for gaining both theoretical and predictive capabilities to more efficiently identify the various thermodynamic and kinetic mechanisms that govern the evolution and stability of structures and phases in these film-substrate systems, and other materials systems in general. In this turnaround experiment the stability of the interface between the base material (Fe-12%Cr binary alloy) and different coatings (yttrium, yttrium oxide, titanium and titanium oxide) will be investigated after irradiation at 300°C, 500°C, and 600°C with 5 MeV Ni2+ ions, up to a dose of ~45 dpa and compared with the as deposited condition. Transmission Electron Microscope samples will be prepared via Focus Ion Beam techniques; the TEM samples will be analyzed at the Macs Suite located in the CAES facility. The whole samples preparation and sample analysis will cover a period of approximately 1 month. The proposed research cross-cuts materials degradation processes in a wide range of nuclear reactor systems that are of relevance to the DoE-NE program. Understanding the role of interfaces in materials degradation under the influence of irradiation and corrosion (oxidation) on a fundamental level is important for the development of new materials that can withstand the extreme environments of nuclear reactors. Furthermore, the deposition of thin films of materials that form highly stable oxide films can improve corrosion resistance of existing code-certified alloys. The research is of particular relevance to nanostructured oxide dispersion strengthened ferritic steels that are strengthened by (Y, Ti) oxide nanoparticles. These steels have very good high temperature mechanical properties, but the stability of the particles (largely dictated by the particle-matrix interface) is not fully understood. The findings of the study can be extended to other nano-structured alloys that under development (e.g. TiC nano-particle-containing austenitic steels).
Additional Info
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| Abstract | Oxide dispersed Strengthen (ODS) steels exhibit an improved response to radiation damage as compared to conventional ferritic and austenitic steels. The stability of the fine dispersion of nanoparticle in the matrix is critical for the application of these steels in new generation nuclear power plants. The interface between the clusters and the matrix, in the steel, plays a key role in dictating its long-term stability under the influence of radiation and high temperatures. To gain a better understanding to the role of interfaces, we are depositing thin films (~ 350 nm in thickness) of yttrium, yttrium oxide, titanium and titanium oxide on substrates of Fe-12%Cr pure binary alloy substrates followed by elevated temperature ion irradiation (with nickel ions). A fundamental understanding of interfacial effects (stability of interfaces under radiation at elevated temperatures, film substrate interface mixing, evolution of defects and other phases at the interface), is crucially important for the development of materials suitable for the extreme environments of a nuclear reactor. Transmission Electron Microscopy (TEM) and Scanning-TEM (STEM) coupled with Energy Dispersive Electron Spectroscopy (EDS) will be used to investigate physical and chemical stability of the interface between the thin films and the substrate on a nanometer scale after radiation at high temperature. In the proposed research, the experimental work will be also integrated with multi-scale computational modeling (molecular and particle dynamics codes), for gaining both theoretical and predictive capabilities to more efficiently identify the various thermodynamic and kinetic mechanisms that govern the evolution and stability of structures and phases in these film-substrate systems, and other materials systems in general. In this turnaround experiment the stability of the interface between the base material (Fe-12%Cr binary alloy) and different coatings (yttrium, yttrium oxide, titanium and titanium oxide) will be investigated after irradiation at 300°C, 500°C, and 600°C with 5 MeV Ni2+ ions, up to a dose of ~45 dpa and compared with the as deposited condition. Transmission Electron Microscope samples will be prepared via Focus Ion Beam techniques; the TEM samples will be analyzed at the Macs Suite located in the CAES facility. The whole samples preparation and sample analysis will cover a period of approximately 1 month. The proposed research cross-cuts materials degradation processes in a wide range of nuclear reactor systems that are of relevance to the DoE-NE program. Understanding the role of interfaces in materials degradation under the influence of irradiation and corrosion (oxidation) on a fundamental level is important for the development of new materials that can withstand the extreme environments of nuclear reactors. Furthermore, the deposition of thin films of materials that form highly stable oxide films can improve corrosion resistance of existing code-certified alloys. The research is of particular relevance to nanostructured oxide dispersion strengthened ferritic steels that are strengthened by (Y, Ti) oxide nanoparticles. These steels have very good high temperature mechanical properties, but the stability of the particles (largely dictated by the particle-matrix interface) is not fully understood. The findings of the study can be extended to other nano-structured alloys that under development (e.g. TiC nano-particle-containing austenitic steels). |
| Award Announced Date | 2013-04-22T00:00:00 |
| 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 | 398 |