NSUF 17-905: Enhancing radiation tolerance through increasing alloy complexity.
Project Objectives: The development of strategies to design structural alloys with enhanced tolerance to radiation damage and concurrently minimize the attendant property degradation enables technologies for next generation reactors.
A new strategy to produce such alloys involves the ability to control how the energy deposited in a metal by an energetic particle is dissipated, and to manipulate the defect migration agglomeration energies. The former reduces the number of point defects surviving the displacement cascade and the latter influences how the defect microstructure evolves with increasing fluence. This control and manipulation will be achieved by adjusting the compositional complexity of the alloy. For example, concentrated solid-solution single-phase alloys possess a high tolerance to damage accumulation, but our understanding and knowledge of how this occurs is just emerging [1-3]. The enhanced resistance is attributed to an increased lifetime of the thermal spike and to higher defect formation and migration barriers [2, 4, 5].
The objective is to determine how the defect structure evolves during continued irradiation, and the response dependence on the material composition, alloying element and irradiation parameters. To this end, single phase ([001]-oriented) of Ni, NiCo, NiFe, NiCoCr, NiCoFeCr, NiCoFeCrMn and NiCoFeCrPd were irradiated in the IVEM facility with 1MeV Kr++ at 773 K up to 2 dpa [6]. The initial results indicated the defect density, defect size, loop form (faulted or unfaulted), loop migration and loop growth rate were dependent on alloy complexity. However, the dependence was not simply on the complexity as some elements were more effective in suppressing defect formation and retarding defect mobility than others [6].
The proposed effort will determine the dependence of the response of this series of alloys on different irradiation parameters (100 keV Kr, 1 MeV Kr, 300 and 600K), as well as the level of segregation to loops (UW-Madison characterization), and the alloy stability under irradiation. Furthermore, irradiations on non-equiatomic binary alloys, e.g. Ni-20Co, Ni-20Pd will be performed to explore the effect of specific element. Determination of responses over several conditions is needed to develop an understanding of the mechanisms responsible for the difference. Results from modeling and simulation studies will be used to enhance the interpretation of these experiments.
Potential impact is the discovery of how alloying with specific elements can be used to manipulate and control the energy dissipation processes through the different subsystems as well as defect migration and agglomeration barriers in metals. That is, limiting the number of defects created, as opposed to increasing annihilation sites. A consequence of this advance is an additional strategy to enhance radiation resistance, which would result in structural materials for nuclear systems with improved properties.
Expected period of performance This project is part of the EFRC at ORNL called Energy Dissipation to Defect Evolution. This project is funded through August, 2018. A total of 10 days over the next year is requested.
References:
- He, M.-R., et al., Acta Materialia, 2017. 126:182-193.
- Zhang, Y., et al., J. Materials Research, 2016. 31: 2363-2375.
- Lu, C., et al., Nature Communications, 2016. 7: p. 13564.
- Béland, L.K., et al.,. Journal of Applied Physics, 2016. 119(8): 085901.
- Zhang, Y., et al., I. Nat Commun, 2015. 6.
- Shi, S., et al., in preparation, 2016.
Additional Info
| Field | Value |
|---|---|
| Abstract | Project Objectives: The development of strategies to design structural alloys with enhanced tolerance to radiation damage and concurrently minimize the attendant property degradation enables technologies for next generation reactors. A new strategy to produce such alloys involves the ability to control how the energy deposited in a metal by an energetic particle is dissipated, and to manipulate the defect migration agglomeration energies. The former reduces the number of point defects surviving the displacement cascade and the latter influences how the defect microstructure evolves with increasing fluence. This control and manipulation will be achieved by adjusting the compositional complexity of the alloy. For example, concentrated solid-solution single-phase alloys possess a high tolerance to damage accumulation, but our understanding and knowledge of how this occurs is just emerging [1-3]. The enhanced resistance is attributed to an increased lifetime of the thermal spike and to higher defect formation and migration barriers [2, 4, 5]. The objective is to determine how the defect structure evolves during continued irradiation, and the response dependence on the material composition, alloying element and irradiation parameters. To this end, single phase ([001]-oriented) of Ni, NiCo, NiFe, NiCoCr, NiCoFeCr, NiCoFeCrMn and NiCoFeCrPd were irradiated in the IVEM facility with 1MeV Kr++ at 773 K up to 2 dpa [6]. The initial results indicated the defect density, defect size, loop form (faulted or unfaulted), loop migration and loop growth rate were dependent on alloy complexity. However, the dependence was not simply on the complexity as some elements were more effective in suppressing defect formation and retarding defect mobility than others [6]. The proposed effort will determine the dependence of the response of this series of alloys on different irradiation parameters (100 keV Kr, 1 MeV Kr, 300 and 600K), as well as the level of segregation to loops (UW-Madison characterization), and the alloy stability under irradiation. Furthermore, irradiations on non-equiatomic binary alloys, e.g. Ni-20Co, Ni-20Pd will be performed to explore the effect of specific element. Determination of responses over several conditions is needed to develop an understanding of the mechanisms responsible for the difference. Results from modeling and simulation studies will be used to enhance the interpretation of these experiments. Potential impact is the discovery of how alloying with specific elements can be used to manipulate and control the energy dissipation processes through the different subsystems as well as defect migration and agglomeration barriers in metals. That is, limiting the number of defects created, as opposed to increasing annihilation sites. A consequence of this advance is an additional strategy to enhance radiation resistance, which would result in structural materials for nuclear systems with improved properties. Expected period of performance This project is part of the EFRC at ORNL called Energy Dissipation to Defect Evolution. This project is funded through August, 2018. A total of 10 days over the next year is requested. References: 1. He, M.-R., et al., Acta Materialia, 2017. 126:182-193. 2. Zhang, Y., et al., J. Materials Research, 2016. 31: 2363-2375. 3. Lu, C., et al., Nature Communications, 2016. 7: p. 13564. 4. Béland, L.K., et al.,. Journal of Applied Physics, 2016. 119(8): 085901. 5. Zhang, Y., et al., I. Nat Commun, 2015. 6. 6. Shi, S., et al., in preparation, 2016. |
| Award Announced Date | 2017-04-26T10:13:44.757 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Wei-Ying Chen |
| Irradiation Facility | None |
| PI | Ian Robertson |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 905 |