NSUF 19-1731: Atom Probe Tomography (APT) Investigation of Radiation Stability of Oxide Nanoclusters in Oxide Dispersion Strengthened (ODS) Steel Manufactured by the Cold Spray Process
The goal of the proposed rapid turnaround experiment (RTE) led by the University of Wisconsin, Madison (UW) is to investigate the stability of oxide nanoparticles in ion-irradiated ODS steel manufactured by the novel cold spray process using Atomic Probe Tomography (APT) (also referred to as Local Electrode Atom Probe (LEAP)). The proposed research would provide extended data showing stability of the cold spray produced ODS steel materials with respect to the number density, size, and composition of the oxide nanparticles under heavy ion irradiation as compared to ODS steel cladding tubes produced by conventional methods. For this investigation, ten days of instrument time is requested on the APT and six days on the Focused Ion Beam (FIB) for APT sample preparation at Idaho National Laboratory (INL). During the cold spray process, gas atomized 14YWT powder particles containing oxide nanoparticles are propelled at supersonic velocities through a converging-diverging nozzle system by pre-heated pressurized gas onto a substrate to form a deposit. The particle temperature is low and deposition occurs in solid state. Under an ongoing NEET project, UW has successfully demonstrated a manufacturing route for ODS steel cladding tubes using the cold spray process [1], but APT is required to achieve the fine-scale spatial resolution needed to understand the physical and compositional stability at the nanoscale (< 5nm) under irradiation. The size, size distribution, and the composition of the oxide nanoparticles, which dictate the high temperature strength of ODS steel, as well as a radiation sink strength of the oxide nanoparticles will be evaluated.
The first question this RTE will seek to answer is about the stability of oxide nanoparticles in the gas atomized 14YWT powder during the cold spray process and their reprecipitation during ion-irradiation. It is hypothesized that the high velocity impact of the oxide nanoparticles in the powder particle during the cold spray process leads to oxide particle dissolution in the ferritic steel matrix, analogous to the high energy ball milling process used in the conventional methods of preparing ODS. Subsequent heavy ion irradiation of the supersaturated solid-solution matrix can potentially result in reprecipitation of the oxide nanoparticles. Investigation of this hypothesis requires APT examination of as-deposited ODS steel and its ion-irradiated counterpart.
The second question this RTE will seek to answer is how cold spray manufactured ODS steel behaves under radiation as compared to conventionally manufactured ODS steel with respect to the number density, composition, and size of the oxide nanoparticles.
Both the above scientific questions in our opinion are most conclusively addressed by the state-of-the-art APT facility at the Idaho National Laboratory.
Supporting work (outside RTE proposal): (i) Ion irradiation of cold spray produced ODS steel samples performed at UW’s accelerator facilities using 3.7 MeV Fe+2 ions to a maximum damage level of 110 dpa. (ii) Continued SEM and S/TEM-EDS characterization of oxide nanoparticles in the ODS steels (produced by both cold spray and conventional methods) at the UW’s Materials Science Center to complement the APT work proposed in this RTE.
Additional Info
| Field | Value |
|---|---|
| Abstract | The goal of the proposed rapid turnaround experiment (RTE) led by the University of Wisconsin, Madison (UW) is to investigate the stability of oxide nanoparticles in ion-irradiated ODS steel manufactured by the novel cold spray process using Atomic Probe Tomography (APT) (also referred to as Local Electrode Atom Probe (LEAP)). The proposed research would provide extended data showing stability of the cold spray produced ODS steel materials with respect to the number density, size, and composition of the oxide nanparticles under heavy ion irradiation as compared to ODS steel cladding tubes produced by conventional methods. For this investigation, ten days of instrument time is requested on the APT and six days on the Focused Ion Beam (FIB) for APT sample preparation at Idaho National Laboratory (INL). During the cold spray process, gas atomized 14YWT powder particles containing oxide nanoparticles are propelled at supersonic velocities through a converging-diverging nozzle system by pre-heated pressurized gas onto a substrate to form a deposit. The particle temperature is low and deposition occurs in solid state. Under an ongoing NEET project, UW has successfully demonstrated a manufacturing route for ODS steel cladding tubes using the cold spray process [1], but APT is required to achieve the fine-scale spatial resolution needed to understand the physical and compositional stability at the nanoscale (< 5nm) under irradiation. The size, size distribution, and the composition of the oxide nanoparticles, which dictate the high temperature strength of ODS steel, as well as a radiation sink strength of the oxide nanoparticles will be evaluated. The first question this RTE will seek to answer is about the stability of oxide nanoparticles in the gas atomized 14YWT powder during the cold spray process and their reprecipitation during ion-irradiation. It is hypothesized that the high velocity impact of the oxide nanoparticles in the powder particle during the cold spray process leads to oxide particle dissolution in the ferritic steel matrix, analogous to the high energy ball milling process used in the conventional methods of preparing ODS. Subsequent heavy ion irradiation of the supersaturated solid-solution matrix can potentially result in reprecipitation of the oxide nanoparticles. Investigation of this hypothesis requires APT examination of as-deposited ODS steel and its ion-irradiated counterpart. The second question this RTE will seek to answer is how cold spray manufactured ODS steel behaves under radiation as compared to conventionally manufactured ODS steel with respect to the number density, composition, and size of the oxide nanoparticles. Both the above scientific questions in our opinion are most conclusively addressed by the state-of-the-art APT facility at the Idaho National Laboratory. Supporting work (outside RTE proposal): (i) Ion irradiation of cold spray produced ODS steel samples performed at UW’s accelerator facilities using 3.7 MeV Fe+2 ions to a maximum damage level of 110 dpa. (ii) Continued SEM and S/TEM-EDS characterization of oxide nanoparticles in the ODS steels (produced by both cold spray and conventional methods) at the UW’s Materials Science Center to complement the APT work proposed in this RTE. |
| Award Announced Date | 2019-05-14T15:54:45.173 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Yaqiao Wu |
| Irradiation Facility | None |
| PI | Mia Lenling |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 1731 |