NSUF 22-4456: Examining microstructures and mechanical properties of neutron and ion irradiated T91, HT9 and 800H alloys
Ion irradiation has been considered as a surrogate for reactor irradiations and has been widely used due to its versatility including high damage rate and low radioactivity. However, the several orders of magnitude higher damage rate of ion irradiation may result in different microstructures and mechanical responses compared with reactor irradiation. Therefore, it is imperative to systematically investigate the quantitative fidelity of ion beam simulation of the neutron irradiation. Due to the simultaneous production of helium in the reactor, a combined implantation of helium with the heavy ions (Fe) was used in this project (fission reactor-relevant value of ~0.1 appm He/dpa) at a temperature about 60 ℃ higher than the corresponding neutron irradiation. The detailed microstructure characterization will focus on the dislocation loops, cavities, G phases, and element segregation on the grain boundaries which are the important factors on the degradation of the mechanical properties under irradiations. A successful simulation requires high similarities in not only neutron-modified microstructures but also neutron-induced bulk properties with those caused by ion irradiation. However, the accurate investigations on the comparison of mechanical properties between neutron and ion irradiations are rare. Besides, the correlation between microstructures and mechanical properties has not been rigorously evaluated. The correlation will provide a promising way to predict the performance of structural materials based on rapid-turnaround ion irradiations.
We proposed to examine five BOR 60 reactor irradiated samples at temperatures of 376, 459 and 462 ℃, with damage level from 17 to 31 dpa, and five dual-ion irradiated samples of grade 91 and HT-9 ferritic/martensitic steels and Alloy 800H at temperatures of 445, 460 and 520 ℃, with damage level at 16.6 and 72 dpa. TEM characterizations will be used to quantify the size and density of dislocation loops, cavities and G phases. And the quantitative results will be applied to the proper hardening models for comparison with the nanoindentation measured hardness on both neutron and dual-ion irradiated samples. We expect a comparable microstructure and hardness will be achieved from the neutron and dual-ion irradiation with a temperature shift of about 60 ℃ on a same alloy. The experiments are expected to start in June 2022 and to be completed before August 2022.
Additional Info
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| Abstract | Ion irradiation has been considered as a surrogate for reactor irradiations and has been widely used due to its versatility including high damage rate and low radioactivity. However, the several orders of magnitude higher damage rate of ion irradiation may result in different microstructures and mechanical responses compared with reactor irradiation. Therefore, it is imperative to systematically investigate the quantitative fidelity of ion beam simulation of the neutron irradiation. Due to the simultaneous production of helium in the reactor, a combined implantation of helium with the heavy ions (Fe) was used in this project (fission reactor-relevant value of ~0.1 appm He/dpa) at a temperature about 60 ℃ higher than the corresponding neutron irradiation. The detailed microstructure characterization will focus on the dislocation loops, cavities, G phases, and element segregation on the grain boundaries which are the important factors on the degradation of the mechanical properties under irradiations. A successful simulation requires high similarities in not only neutron-modified microstructures but also neutron-induced bulk properties with those caused by ion irradiation. However, the accurate investigations on the comparison of mechanical properties between neutron and ion irradiations are rare. Besides, the correlation between microstructures and mechanical properties has not been rigorously evaluated. The correlation will provide a promising way to predict the performance of structural materials based on rapid-turnaround ion irradiations. We proposed to examine five BOR 60 reactor irradiated samples at temperatures of 376, 459 and 462 ℃, with damage level from 17 to 31 dpa, and five dual-ion irradiated samples of grade 91 and HT-9 ferritic/martensitic steels and Alloy 800H at temperatures of 445, 460 and 520 ℃, with damage level at 16.6 and 72 dpa. TEM characterizations will be used to quantify the size and density of dislocation loops, cavities and G phases. And the quantitative results will be applied to the proper hardening models for comparison with the nanoindentation measured hardness on both neutron and dual-ion irradiated samples. We expect a comparable microstructure and hardness will be achieved from the neutron and dual-ion irradiation with a temperature shift of about 60 ℃ on a same alloy. The experiments are expected to start in June 2022 and to be completed before August 2022. |
| Award Announced Date | 2022-06-14T07:25:18.7 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Kory Linton |
| Irradiation Facility | None |
| PI | Pengcheng Zhu |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 4456 |