NSUF 14-482: Neutron Irradiation Effects on Microstructure Properties of Ultra-Fine Grained Steel
Effect of radiation exposure on nano and ultra-fine grain structured metals is 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 nano and ultra-fine grain 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. Very limited amount of research conducted in this area was a motivation to initiate the proposed study. This project is proposed to perform post irradiation examination (PIE) of ATR irradiated ultra-fine grained carbon steel along with its conventional counterpart. The proposed PIE involves Local Electron Atom Probe (LEAP), Transmitted Electron Microscopy (TEM) and Electron Back-Scatter Diffraction (EBSD)of 2 dpa samples. The expected period of performance is 2 months.These results on carbon steel along with those obtained from PULSTAR reactor at NC State to relatively low dpa (~0.001 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 irradiation of ultra-fine 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 nano and ultra-fine grain structured metals is 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 nano and ultra-fine grain 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. Very limited amount of research conducted in this area was a motivation to initiate the proposed study. This project is proposed to perform post irradiation examination (PIE) of ATR irradiated ultra-fine grained carbon steel along with its conventional counterpart. The proposed PIE involves Local Electron Atom Probe (LEAP), Transmitted Electron Microscopy (TEM) and Electron Back-Scatter Diffraction (EBSD)of 2 dpa samples. The expected period of performance is 2 months.These results on carbon steel along with those obtained from PULSTAR reactor at NC State to relatively low dpa (~0.001 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 irradiation of ultra-fine 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 | 2014-02-10T00:00:00 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Yaqiao Wu |
| Irradiation Facility | None |
| PI | Korukonda Murty |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 482 |