NSUF 20-2984: Creation of gas bubble superlattice in tungsten and tungsten alloys
The objective of this proposal is to create gas bubble superlattice (GBS) in tungsten (W) and tungsten-rhenium (W-Re) alloys by using ion implantation. Under irradiation, the formation of gas bubbles leads to a microstructural evolution where gas bubbles usually cause hardening and embrittlement, degrading the mechanical properties of fuels and materials. Managing the gas bubble formation and transforming them from a liability into an asset in a controllable way will help us tailor the microstructure of nuclear materials and precisely predict the materials performance in nuclear reactors. GBS has been observed for decades, they can form either by gas ion implantation or by nuclear transmutation. Although many possible GBS formation mechanisms have been proposed previously, a clear understanding is still missing. The self-organization of gas bubbles typically form bubble superlattice by adopting the same structure as the matrix crystal structure. All ion-irradiation-induced GBSs reported in literature exhibit a superlattice structure with the same crystal orientation to the host materials. However, Gan et al. recently reported that Xenon bubbles form an fcc superlattice in a bcc uranium-molybdenum alloy under neutron irradiation. It was believed that fast 1-D migration of interstitials along directions in the bcc U-Mo matrix causes the gas bubble alignment along directions. Fundamental understanding on the GBS formation in materials is critical for the development of advanced materials in nuclear energy systems. The TEM in-situ He or Kr ion implantation, irradiation and characterization proposed in this RTE will help us understand the role of 1D diffusion of self-interstitial-atoms on GBS formation, and the necessary dynamics of GBS formation for heavy gas ions like Kr and Xe. If successful, it will help to close the knowledge gap on GBS formation mechanism and bring us closer to materials by design approach for advanced nuclear fuels.
Additional Info
| Field | Value |
|---|---|
| Abstract | The objective of this proposal is to create gas bubble superlattice (GBS) in tungsten (W) and tungsten-rhenium (W-Re) alloys by using ion implantation. Under irradiation, the formation of gas bubbles leads to a microstructural evolution where gas bubbles usually cause hardening and embrittlement, degrading the mechanical properties of fuels and materials. Managing the gas bubble formation and transforming them from a liability into an asset in a controllable way will help us tailor the microstructure of nuclear materials and precisely predict the materials performance in nuclear reactors. GBS has been observed for decades, they can form either by gas ion implantation or by nuclear transmutation. Although many possible GBS formation mechanisms have been proposed previously, a clear understanding is still missing. The self-organization of gas bubbles typically form bubble superlattice by adopting the same structure as the matrix crystal structure. All ion-irradiation-induced GBSs reported in literature exhibit a superlattice structure with the same crystal orientation to the host materials. However, Gan et al. recently reported that Xenon bubbles form an fcc superlattice in a bcc uranium-molybdenum alloy under neutron irradiation. It was believed that fast 1-D migration of interstitials along <110> directions in the bcc U-Mo matrix causes the gas bubble alignment along <110> directions. Fundamental understanding on the GBS formation in materials is critical for the development of advanced materials in nuclear energy systems. The TEM in-situ He or Kr ion implantation, irradiation and characterization proposed in this RTE will help us understand the role of 1D diffusion of self-interstitial-atoms on GBS formation, and the necessary dynamics of GBS formation for heavy gas ions like Kr and Xe. If successful, it will help to close the knowledge gap on GBS formation mechanism and bring us closer to materials by design approach for advanced nuclear fuels. |
| Award Announced Date | 2020-02-05T14:09:19.327 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Alina Zackrone, Wei-Ying Chen |
| Irradiation Facility | Intermediate Voltage Electron Microscopy (IVEM)-Tandem Facility |
| PI | Jian Gan |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 2984 |