NSUF 17-1122: Enhanced irradiation tolerance of high-entropy alloys
Efforts are undergoing to extend the life of current reactors and develop advanced reactors, which requires nuclear materials with improved properties (e.g., irradiation tolerance, mechanical properties, and corrosion resistance). However, currently used materials sometimes cannot meet the demanding requirements, and life extension of current reactors and development of advanced reactors can be limited by materials. Hence, it is very important to develop and evaluate new materials for potential application in nuclear reactors. HEAs are a new class of alloys. In contrast to conventional alloys that contain one principal element with minor alloying elements, there are multiple (usually five or above) principal elements in almost equal proportions in HEAs. Intermetallics or complex phases are generally absent in HEAs; the free energy of mixing is significantly reduced by the high entropy of mixing, and consequently random solid-solution phases with simple crystal structures are favored compared to ordered phases. HEAs possess significantly improved mechanical properties than conventional alloys, such as high strength-weight ratio, fracture resistance, high-temperature strength and structural stability. Furthermore, HEAs have been proposed to possess significantly enhanced irradiation tolerance. Hence, HEAs could be new candidate materials for use as structural materials or fuel cladding in nuclear reactors. There have been some limited radiation damage studies of HEAs in the literature. However, in most of the reported irradiation studies on HEAs, Co-containing HEAs were used. It is well known that materials containing Co are not suitable for nuclear applications due to long-term activation issues. This proposed work will systematically study the irradiation performance of Co-free HEAs that were designed and developed for nuclear applications, assess their potential applications in LWRs and advanced fast reactors as structural materials or fuel cladding, and establish/enhance our fundamental understanding of irradiation effects in these materials. The establishment of irradiation performance of novel advanced materials with appealing properties will impact the life extension of current reactors and the development of advanced reactors. Hence, the proposed research is highly relevant to DOE-NE’s Light Water Reactor Sustainability program and Advanced Fast Reactor program. The project will use ion irradiation to study irradiation behavior. HEAs with different compositions will be subjected to ion irradiation at different temperatures to different doses. The project will include 2 sets of HEA samples: (1) Fe30Mn30Ni30Cr10; (2) (Fe30Mn30Ni30Cr10)94T2Al4 or equivalently Fe28.2Ni28.2Mn28.2Cr9.4Ti2Al4. Fe30Mn30Ni30Cr10 is a single-phase face-centered cubic (FCC) structured HEA. (Fe30Mn30Ni30Cr10)94Ti2Al4 or equivalently Fe28.2Ni28.2Mn28.2Cr9.4Ti2Al4 is composed of Fe30Mn30Ni30Cr10 FCC matrix and Ti-Al precipitates. Irradiation behavior of the two HEAs with different structure and compositions will be compared to study the effects of structure and composition on irradiation tolerance. Specifically, the role of Ti-Al precipitates in further enhancing irradiation resistance will be investigated. The post-irradiation examination will include mechanical testing and microstructural examination. Mechanical properties and microstructures of the HEA samples after irradiation will be compared to those before irradiation so that the irradiation effects on microstructural evolution and mechanical properties can be determined, with focus on irradiation-induced hardening, solute segregation, and phase transformation. The expected period of performance is Oct. 2017 - Apr. 2018.
Additional Info
| Field | Value |
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| Abstract | Efforts are undergoing to extend the life of current reactors and develop advanced reactors, which requires nuclear materials with improved properties (e.g., irradiation tolerance, mechanical properties, and corrosion resistance). However, currently used materials sometimes cannot meet the demanding requirements, and life extension of current reactors and development of advanced reactors can be limited by materials. Hence, it is very important to develop and evaluate new materials for potential application in nuclear reactors. HEAs are a new class of alloys. In contrast to conventional alloys that contain one principal element with minor alloying elements, there are multiple (usually five or above) principal elements in almost equal proportions in HEAs. Intermetallics or complex phases are generally absent in HEAs; the free energy of mixing is significantly reduced by the high entropy of mixing, and consequently random solid-solution phases with simple crystal structures are favored compared to ordered phases. HEAs possess significantly improved mechanical properties than conventional alloys, such as high strength-weight ratio, fracture resistance, high-temperature strength and structural stability. Furthermore, HEAs have been proposed to possess significantly enhanced irradiation tolerance. Hence, HEAs could be new candidate materials for use as structural materials or fuel cladding in nuclear reactors. There have been some limited radiation damage studies of HEAs in the literature. However, in most of the reported irradiation studies on HEAs, Co-containing HEAs were used. It is well known that materials containing Co are not suitable for nuclear applications due to long-term activation issues. This proposed work will systematically study the irradiation performance of Co-free HEAs that were designed and developed for nuclear applications, assess their potential applications in LWRs and advanced fast reactors as structural materials or fuel cladding, and establish/enhance our fundamental understanding of irradiation effects in these materials. The establishment of irradiation performance of novel advanced materials with appealing properties will impact the life extension of current reactors and the development of advanced reactors. Hence, the proposed research is highly relevant to DOE-NE’s Light Water Reactor Sustainability program and Advanced Fast Reactor program. The project will use ion irradiation to study irradiation behavior. HEAs with different compositions will be subjected to ion irradiation at different temperatures to different doses. The project will include 2 sets of HEA samples: (1) Fe30Mn30Ni30Cr10; (2) (Fe30Mn30Ni30Cr10)94T2Al4 or equivalently Fe28.2Ni28.2Mn28.2Cr9.4Ti2Al4. Fe30Mn30Ni30Cr10 is a single-phase face-centered cubic (FCC) structured HEA. (Fe30Mn30Ni30Cr10)94Ti2Al4 or equivalently Fe28.2Ni28.2Mn28.2Cr9.4Ti2Al4 is composed of Fe30Mn30Ni30Cr10 FCC matrix and Ti-Al precipitates. Irradiation behavior of the two HEAs with different structure and compositions will be compared to study the effects of structure and composition on irradiation tolerance. Specifically, the role of Ti-Al precipitates in further enhancing irradiation resistance will be investigated. The post-irradiation examination will include mechanical testing and microstructural examination. Mechanical properties and microstructures of the HEA samples after irradiation will be compared to those before irradiation so that the irradiation effects on microstructural evolution and mechanical properties can be determined, with focus on irradiation-induced hardening, solute segregation, and phase transformation. The expected period of performance is Oct. 2017 - Apr. 2018. |
| Award Announced Date | 2017-09-20T12:33:44.99 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Kumar Sridharan |
| Irradiation Facility | None |
| PI | Haiming Wen |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 1122 |