NSUF 15-556: Investigation of precipitate formation kinetics and interactions in FeCrAl alloys
The objective of this project is to investigate the factors affecting alpha’ precipitation in neutron irradiated ODS and non-ODS FeCrAl alloys as well as the mechanism for corrosive attack of molten Pb-Li eutectic on ODS FeCrAl. The precipitation of the alpha’ phase has been previously studied in irradiated Fe-Cr binary systems but little to no work has been performed on the ternary FeCrAl system. Al addition is expected to shift the alpha-alpha’ phase boundary to higher Cr compositions, but this has not been confirmed in the irradiated state. Furthermore, details on how alpha’ precipitation kinetics or corrosion resistance are affected by oxide nanoclusters is yet to be determined. Preliminary transmission electron microscopy (TEM) and atom probe tomography (APT) results have shown that the scale formed during Pb-Li exposure of Kanthal APMT, a commercially available ODS FeCrAl alloy, is inward-growing and that Li ingress is most prominently observed at or near ODS particles. This project requires advanced microanalysis techniques including focused ion beam (FIB) sample fabrication and APT. FIB fabrication is required to reduce the total sample activity level while creating the sample geometry necessary to perform APT analysis. APT analysis provides data that allows for quantification and visualization of the size, number density and composition of precipitates contained within the bulk matrix. This data allows for the understanding of the precipitation mechanisms and resulting mechanical/corrosive performance in FeCrAl alloys exposed to extreme environments relevant to nuclear applications including neutron irradiation and corrosive media attack, thereby addressing the current knowledge gaps in the FeCrAl alloy class. The fundamental understanding of precipitation kinetics in the FeCrAl alloy class will increase the technology readiness level of FeCrAl alloys. Furthermore, this work serves as a direct correlation study to Fe-Cr alloys currently under investigation as part of the ATR-1 and ATR-2 irradiation experiment. On the whole, information gained from the proposed work will have broad reaching impacts on ferrous-based alloy development for nuclear power generation including cladding, structural materials, and corrosion barrier systems in fusion and fission systems. This project is predicted to take no more than 5 months to complete. Fabrication of APT samples using FIB techniques is estimated to take no more than 2 months. Data collection of APT samples is expected to take less than two weeks. Data analysis and reporting will take approximately 2 months from the date of initial data collection.
Additional Info
| Field | Value |
|---|---|
| Abstract | The objective of this project is to investigate the factors affecting alpha’ precipitation in neutron irradiated ODS and non-ODS FeCrAl alloys as well as the mechanism for corrosive attack of molten Pb-Li eutectic on ODS FeCrAl. The precipitation of the alpha’ phase has been previously studied in irradiated Fe-Cr binary systems but little to no work has been performed on the ternary FeCrAl system. Al addition is expected to shift the alpha-alpha’ phase boundary to higher Cr compositions, but this has not been confirmed in the irradiated state. Furthermore, details on how alpha’ precipitation kinetics or corrosion resistance are affected by oxide nanoclusters is yet to be determined. Preliminary transmission electron microscopy (TEM) and atom probe tomography (APT) results have shown that the scale formed during Pb-Li exposure of Kanthal APMT, a commercially available ODS FeCrAl alloy, is inward-growing and that Li ingress is most prominently observed at or near ODS particles. This project requires advanced microanalysis techniques including focused ion beam (FIB) sample fabrication and APT. FIB fabrication is required to reduce the total sample activity level while creating the sample geometry necessary to perform APT analysis. APT analysis provides data that allows for quantification and visualization of the size, number density and composition of precipitates contained within the bulk matrix. This data allows for the understanding of the precipitation mechanisms and resulting mechanical/corrosive performance in FeCrAl alloys exposed to extreme environments relevant to nuclear applications including neutron irradiation and corrosive media attack, thereby addressing the current knowledge gaps in the FeCrAl alloy class. The fundamental understanding of precipitation kinetics in the FeCrAl alloy class will increase the technology readiness level of FeCrAl alloys. Furthermore, this work serves as a direct correlation study to Fe-Cr alloys currently under investigation as part of the ATR-1 and ATR-2 irradiation experiment. On the whole, information gained from the proposed work will have broad reaching impacts on ferrous-based alloy development for nuclear power generation including cladding, structural materials, and corrosion barrier systems in fusion and fission systems. This project is predicted to take no more than 5 months to complete. Fabrication of APT samples using FIB techniques is estimated to take no more than 2 months. Data collection of APT samples is expected to take less than two weeks. Data analysis and reporting will take approximately 2 months from the date of initial data collection. |
| Award Announced Date | 2015-04-22T00:00:00 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Yaqiao Wu |
| Irradiation Facility | None |
| PI | Samuel A. Briggs |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 556 |