NSUF 20-4094: Radiation effect to the deformation mechanism of Alloys 800H and 800H-TMP
The goal of the project is to investigate the radiation effect on the deformation mechanism of alloys 800H and 800H-TMP (thermomechanical processed). Alloy 800H is being considered for the Next Generation Nuclear Plant and Molten Salt Reactors, as well as the Advanced Radiation-Resistant Materials program partnered with the Light Water Reactor Sustainability program. Austenitic stainless steels show dependence of deformation mechanism on grain orientation. The exposure of austenitic stainless steels to reactor environment leads to the formation of dislocation loops, cavity, and γ’ precipitates, which interact with the strain-induced defects under loading. Therefore, the irradiation will influence the deformation of austenitic stainless steels. Previous studies demonstrated the martensite formation at dislocation channels in {001} and {111} grains that are parallel to the loading direction in irradiated 304 austenitic stainless steel. Alloy 800H/800H-TMP has a higher Ni content by ~20%, which restricts the ferrite/martensite formation. The radiation effect on the deformation mechanism on the high Ni-content austenitic stainless steels, 800H/800H-TMP, has not been systematically studied. In this project, we propose to use SEM in-situ nanoindentation, electron backscatter diffraction (EBSD), focused-ion beam (FIB), and transmission electron microscopy (TEM) to investigate the deformation mechanisms of irradiated alloys 800H and 800H-TMP, with an expected performance period of six months after the award of the proposal. SEM in-situ nanoindentation will be performed on the irradiated samples of alloys 800H and 800H-TMP. Indentations on the {001}, {011}, and {111} grains will be identified by EBSD for FIB lift-out. All TEM foils will be lift out at the selected indents using the same foil-indent orientation, followed by the TEM microstructure characterization. Careful comparison between different grain orientation and different samples will be performed at the same regions from the indent tips, acknowledging the stress distribution under the indents. By comparing with the on-going deformation mechanism study of unirradiated alloys 800H and 800H-TMP, the outcome of this proposal on the irradiated alloys will provide fundamental understanding on the irradiation effect to the deformation mechanism of alloys 800H and 800H-TMP. In addition, the effect of TMP on the deformation mechanism after irradiation will be revealed. The knowledge from this proposal will enable us to envision the mechanical response of high-Ni content austenitic stainless steels in reactor environments.
Additional Info
| Field | Value |
|---|---|
| Abstract | The goal of the project is to investigate the radiation effect on the deformation mechanism of alloys 800H and 800H-TMP (thermomechanical processed). Alloy 800H is being considered for the Next Generation Nuclear Plant and Molten Salt Reactors, as well as the Advanced Radiation-Resistant Materials program partnered with the Light Water Reactor Sustainability program. Austenitic stainless steels show dependence of deformation mechanism on grain orientation. The exposure of austenitic stainless steels to reactor environment leads to the formation of dislocation loops, cavity, and γ’ precipitates, which interact with the strain-induced defects under loading. Therefore, the irradiation will influence the deformation of austenitic stainless steels. Previous studies demonstrated the martensite formation at dislocation channels in {001} and {111} grains that are parallel to the loading direction in irradiated 304 austenitic stainless steel. Alloy 800H/800H-TMP has a higher Ni content by ~20%, which restricts the ferrite/martensite formation. The radiation effect on the deformation mechanism on the high Ni-content austenitic stainless steels, 800H/800H-TMP, has not been systematically studied. In this project, we propose to use SEM in-situ nanoindentation, electron backscatter diffraction (EBSD), focused-ion beam (FIB), and transmission electron microscopy (TEM) to investigate the deformation mechanisms of irradiated alloys 800H and 800H-TMP, with an expected performance period of six months after the award of the proposal. SEM in-situ nanoindentation will be performed on the irradiated samples of alloys 800H and 800H-TMP. Indentations on the {001}, {011}, and {111} grains will be identified by EBSD for FIB lift-out. All TEM foils will be lift out at the selected indents using the same foil-indent orientation, followed by the TEM microstructure characterization. Careful comparison between different grain orientation and different samples will be performed at the same regions from the indent tips, acknowledging the stress distribution under the indents. By comparing with the on-going deformation mechanism study of unirradiated alloys 800H and 800H-TMP, the outcome of this proposal on the irradiated alloys will provide fundamental understanding on the irradiation effect to the deformation mechanism of alloys 800H and 800H-TMP. In addition, the effect of TMP on the deformation mechanism after irradiation will be revealed. The knowledge from this proposal will enable us to envision the mechanical response of high-Ni content austenitic stainless steels in reactor environments. |
| Award Announced Date | 2020-07-14T14:03:24.017 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Kory Linton |
| Irradiation Facility | None |
| PI | Weicheng Zhong |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 4094 |