NSUF 14-485: Correlating mechanical properties with microstructure evolution in irradiated F/M and ODS alloys
Ferritic/martensitic (F/M) and oxide-dispersion strengthened (ODS) alloys are leading candidates for structural components in fusion and fast fission reactors, because of their high-temperature strength, dimensional stability, and low activation. Many studies have focused on the microstructure evolution of these alloys under irradiation, while others have focused on irradiation-induced mechanical property changes. The proposed work seeks to merge the microstructural and mechanical approaches to obtain an understanding of how irradiation-induced mechanical property changes may be attributed to individual microstructural features. Results of the proposed work will be applicable not only to F/M and ODS alloys, but will also be relevant for other irradiated metals and alloys. The proposer has recently conducted a comparable study on Fe-9Cr ODS irradiated with 5.0 MeV Fe++ ions to 100 dpa at 400°C. Hardness measured through nanoindentation was correlated with the hardening contributions from irradiation-induced microstructural changes. Nanoindentation results suggest approximately 127 MPa increase in hardening due to irradiation. Because of the high density of loops, dislocations, and oxides in F/M and ODS alloys, total hardening was calculated with features additive (H_tot=H_lines+H_loops+H_oxides) and superpositioned (H_tot=sqrt((H_lines^2)+(H_loops^2)+(H_oxides^2))). Calculated hardening from microstructure analysis ranged 67¬–152 MPa. These results suggest moderate agreement between nanoindentation and microstructure, although factors such as grain size, RIS, precipitation, and hardness gradients across denuded zones have yet to be taken into account. The proposed work will consider these factors, and will determine whether it is appropriate to superposition hardening contributions. This project will focus on the mechanical and microstructural characterization of ion- and neutron-irradiated F/M and ODS alloys T91, HT9, and Fe-9Cr ODS. Microstructure characterization will be carried out through a combination of transmission electron microscopy (TEM) and local electrode atom probe (LEAP). Mechanical characterization will include microhardness and nanohardness measurements. Two sets of the same heats of alloys will be studied: a first set irradiated with 5.0 MeV Fe++ ions (~10-3 dpa/sec) to 100 dpa at 500°C, which are in the PI’s possession, and a second set irradiated in the Advanced Test Reactor (~10-7 dpa/sec) to 3 dpa at 500°C (sample library 019-331, 018-331, and 023-331). This proposal requests access to the Microscopy and Characterization Suite (MaCS) at the Center for Advanced Energy Studies (CAES), for 3 days on the FEI Quanta focused ion beam, 4 days on the CAMECA 4000X HR LEAP, 2 days on the FEI Tecnai TEM, 3 days on the Hysitron TriboIndenter, and 1 day of microhardness testing.
추가 정보
| 필드 | 값 |
|---|---|
| Abstract | Ferritic/martensitic (F/M) and oxide-dispersion strengthened (ODS) alloys are leading candidates for structural components in fusion and fast fission reactors, because of their high-temperature strength, dimensional stability, and low activation. Many studies have focused on the microstructure evolution of these alloys under irradiation, while others have focused on irradiation-induced mechanical property changes. The proposed work seeks to merge the microstructural and mechanical approaches to obtain an understanding of how irradiation-induced mechanical property changes may be attributed to individual microstructural features. Results of the proposed work will be applicable not only to F/M and ODS alloys, but will also be relevant for other irradiated metals and alloys. The proposer has recently conducted a comparable study on Fe-9Cr ODS irradiated with 5.0 MeV Fe++ ions to 100 dpa at 400°C. Hardness measured through nanoindentation was correlated with the hardening contributions from irradiation-induced microstructural changes. Nanoindentation results suggest approximately 127 MPa increase in hardening due to irradiation. Because of the high density of loops, dislocations, and oxides in F/M and ODS alloys, total hardening was calculated with features additive (H_tot=H_lines+H_loops+H_oxides) and superpositioned (H_tot=sqrt((H_lines^2)+(H_loops^2)+(H_oxides^2))). Calculated hardening from microstructure analysis ranged 67¬–152 MPa. These results suggest moderate agreement between nanoindentation and microstructure, although factors such as grain size, RIS, precipitation, and hardness gradients across denuded zones have yet to be taken into account. The proposed work will consider these factors, and will determine whether it is appropriate to superposition hardening contributions. This project will focus on the mechanical and microstructural characterization of ion- and neutron-irradiated F/M and ODS alloys T91, HT9, and Fe-9Cr ODS. Microstructure characterization will be carried out through a combination of transmission electron microscopy (TEM) and local electrode atom probe (LEAP). Mechanical characterization will include microhardness and nanohardness measurements. Two sets of the same heats of alloys will be studied: a first set irradiated with 5.0 MeV Fe++ ions (~10-3 dpa/sec) to 100 dpa at 500°C, which are in the PI’s possession, and a second set irradiated in the Advanced Test Reactor (~10-7 dpa/sec) to 3 dpa at 500°C (sample library 019-331, 018-331, and 023-331). This proposal requests access to the Microscopy and Characterization Suite (MaCS) at the Center for Advanced Energy Studies (CAES), for 3 days on the FEI Quanta focused ion beam, 4 days on the CAMECA 4000X HR LEAP, 2 days on the FEI Tecnai TEM, 3 days on the Hysitron TriboIndenter, and 1 day of microhardness testing. |
| Award Announced Date | 2014-02-10T00:00:00 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Yaqiao Wu |
| Irradiation Facility | None |
| PI | Janelle Wharry |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 485 |