NSUF 18-1491: Evaluating void swelling and microstructure evolution of additively manufactured HT9
The objective of this work is to evaluate the swelling characteristics of HT9 fabricated using additive manufacturing. Mechanical properties of HT9 fabricated using AM in the unirradiated state has been examined and it has been shown that the AM processed HT9 in the as fabricated state and post processed state exceed the performance of conventional wrought materials. However, to prove that AM is a viable technique to process ferritic martensitic steels, swelling during irradiation needs to be evaluated. There is no study thus far to evaluate swelling in HT9 processed using AM. The proposed study will address this gap by subjecting HT9 in 4 conditions including wrought state (control), Processed using AM, post-processed using heat treatment I (1065°C/30minutes+760°C/1h) and post-processed using heat treatment II (1040°C/30 minutes+ 740°C/1h) to ion irradiation. The study would seek to examine the void sizes, void distribution, swelling and microstructure evolution after irradiation to a total accumulated damage dose of 50 dpa at temperature of 460 °C at a dose rate of 5x10-4 dpa/s. This dose, dose rate and temperature is known to act as a rapid screening to evaluate the swelling resistance of HT9. Ferritic martensitic steels are candidate materials for high burnup scenarios and hence they will operate at elevated temperatures and doses which can exceed 100 dpa. The result is the radiation-induced microstructure needs to be evaluated up to and above 100 dpa for any candidate material and/or processing route. Since it is not practical to achieve those doses in a test reactor, dual-beam ion irradiation - which can simulated neutron damage - becomes necessary. This proposal seeks to use the ion irradiation facility housed at the Michigan Ion Beam Laboratory (MIBL) at University of Michigan, a NSUF partner facility. Following irradiation, S/TEM analysis will be performed to characterize the void distribution and swelling rates in the AM produced HT9. In addition, TEM analysis will yield information on secondary phases and radiation-induced segregation. The data collection on these effects will then be compared with wrought HT9. The fundamental understanding of microstructure evolution during irradiation of HT9 will improve the overall technology awareness level of additive manufacturing technologies. This project will have far reaching impact in the fission technologies including various advanced reactor concepts and the Versatile Test Reactor (VTR) concept. The overall NSUF portion of this project (MIBL irradiation) is estimated to be complete in 1 week followed by 1 month of non-NSUF supported characterization efforts using S/TEM-based techniques.
Additional Info
| Field | Value |
|---|---|
| Abstract | The objective of this work is to evaluate the swelling characteristics of HT9 fabricated using additive manufacturing. Mechanical properties of HT9 fabricated using AM in the unirradiated state has been examined and it has been shown that the AM processed HT9 in the as fabricated state and post processed state exceed the performance of conventional wrought materials. However, to prove that AM is a viable technique to process ferritic martensitic steels, swelling during irradiation needs to be evaluated. There is no study thus far to evaluate swelling in HT9 processed using AM. The proposed study will address this gap by subjecting HT9 in 4 conditions including wrought state (control), Processed using AM, post-processed using heat treatment I (1065°C/30minutes+760°C/1h) and post-processed using heat treatment II (1040°C/30 minutes+ 740°C/1h) to ion irradiation. The study would seek to examine the void sizes, void distribution, swelling and microstructure evolution after irradiation to a total accumulated damage dose of 50 dpa at temperature of 460 °C at a dose rate of 5x10-4 dpa/s. This dose, dose rate and temperature is known to act as a rapid screening to evaluate the swelling resistance of HT9. Ferritic martensitic steels are candidate materials for high burnup scenarios and hence they will operate at elevated temperatures and doses which can exceed 100 dpa. The result is the radiation-induced microstructure needs to be evaluated up to and above 100 dpa for any candidate material and/or processing route. Since it is not practical to achieve those doses in a test reactor, dual-beam ion irradiation - which can simulated neutron damage - becomes necessary. This proposal seeks to use the ion irradiation facility housed at the Michigan Ion Beam Laboratory (MIBL) at University of Michigan, a NSUF partner facility. Following irradiation, S/TEM analysis will be performed to characterize the void distribution and swelling rates in the AM produced HT9. In addition, TEM analysis will yield information on secondary phases and radiation-induced segregation. The data collection on these effects will then be compared with wrought HT9. The fundamental understanding of microstructure evolution during irradiation of HT9 will improve the overall technology awareness level of additive manufacturing technologies. This project will have far reaching impact in the fission technologies including various advanced reactor concepts and the Versatile Test Reactor (VTR) concept. The overall NSUF portion of this project (MIBL irradiation) is estimated to be complete in 1 week followed by 1 month of non-NSUF supported characterization efforts using S/TEM-based techniques. |
| Award Announced Date | 2018-05-17T11:21:07.533 |
| Awarded Institution | Center for Advanced Energy Studies |
| Facility | Microscopy and Characterization Suite |
| Facility Tech Lead | Kevin Field, Yaqiao Wu |
| Irradiation Facility | None |
| PI | Niyanth Sridharan |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 1491 |