NSUF 12-332: Post Irradiation Examination of ATR-irradiated Nanocrystalline Materials
Effect of radiation exposure on nanograin structured metals will be of immense interest both from scientific and technological points of view. While in conventional metals, radiation produces various defects (point, line, surface and volume), it is not clear how these defects especially dislocations (line defects) and stacking faults (surface defects) can be accommodated in the relatively minute grains of nm-scale. The response of nanograin structured metals to neutron irradiation can be expected to be different from their large grained equivalents and this response could be in terms of the changes in mechanical properties post neutron irradiation or it could be an altered microstructure altogether. It is well known that the induced point defects and their clusters, due to irradiation, can migrate and annihilate at the interfaces of materials and accordingly, nanograin structured metals should possess good resistance to irradiation because the large volume fraction of grain boundaries can act as an important sink for radiation-induced defects. Very limited amount of research conducted in this area was a motivation to initiate the proposed study since the few attempts to study the effects of radiation on nanograin structured metals were only limited to observing the developed microstructure, and radiation effects on mechanical properties and the effect of processing routes were not considered to-date. The present study aims to investigate these effects in varied metallic systems including pure metals and alloys. This Rapid Turnaround project is proposed to perform post irradiation examination (PIE) of ATR irradiated ultrafine grained carbon steel along with its conventional counterpart. The proposed PIE involves microhardness and tensile testing of 1-dpa samples along with microstructural characterization using optical, transmission and scanning electron microscopies at INL’s MFC and CAES. The expected period of performance is for 3 months from mid-March 2012. These results on carbon steel along with those obtained from PULSTAR reactor at NC State to relatively low dpa (~0.2 dpa) will enable us to investigate the influence of neutron irradiation on Hall-Petch relation. Earlier work on fcc Cu revealed decreased source hardening resulting in reduction of the slope of Hall-Petch plot and the current study will shed light on the plausible effect of crystal structure (bcc vs fcc). Moreover, low dose irradiations of ultrafine grained carbon steel revealed essentially no radiation hardening in contrast to radiation softening noted in Cu due to in-situ grain growth; radiation effects at higher dose will be beneficial in examining these phenomena and providing evidence as to the superior radiation resistance of ultra and nano grain sized materials.
Additional Info
| Field | Value |
|---|---|
| Abstract | Effect of radiation exposure on nanograin structured metals will be of immense interest both from scientific and technological points of view. While in conventional metals, radiation produces various defects (point, line, surface and volume), it is not clear how these defects especially dislocations (line defects) and stacking faults (surface defects) can be accommodated in the relatively minute grains of nm-scale. The response of nanograin structured metals to neutron irradiation can be expected to be different from their large grained equivalents and this response could be in terms of the changes in mechanical properties post neutron irradiation or it could be an altered microstructure altogether. It is well known that the induced point defects and their clusters, due to irradiation, can migrate and annihilate at the interfaces of materials and accordingly, nanograin structured metals should possess good resistance to irradiation because the large volume fraction of grain boundaries can act as an important sink for radiation-induced defects. Very limited amount of research conducted in this area was a motivation to initiate the proposed study since the few attempts to study the effects of radiation on nanograin structured metals were only limited to observing the developed microstructure, and radiation effects on mechanical properties and the effect of processing routes were not considered to-date. The present study aims to investigate these effects in varied metallic systems including pure metals and alloys. This Rapid Turnaround project is proposed to perform post irradiation examination (PIE) of ATR irradiated ultrafine grained carbon steel along with its conventional counterpart. The proposed PIE involves microhardness and tensile testing of 1-dpa samples along with microstructural characterization using optical, transmission and scanning electron microscopies at INL’s MFC and CAES. The expected period of performance is for 3 months from mid-March 2012. These results on carbon steel along with those obtained from PULSTAR reactor at NC State to relatively low dpa (~0.2 dpa) will enable us to investigate the influence of neutron irradiation on Hall-Petch relation. Earlier work on fcc Cu revealed decreased source hardening resulting in reduction of the slope of Hall-Petch plot and the current study will shed light on the plausible effect of crystal structure (bcc vs fcc). Moreover, low dose irradiations of ultrafine grained carbon steel revealed essentially no radiation hardening in contrast to radiation softening noted in Cu due to in-situ grain growth; radiation effects at higher dose will be beneficial in examining these phenomena and providing evidence as to the superior radiation resistance of ultra and nano grain sized materials. |
| Award Announced Date | 2012-02-27T00:00:00 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Alina Zackrone, Yaqiao Wu |
| Irradiation Facility | None |
| PI | Korukonda Murty |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 332 |