| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Mechanical Behavior of Nuclear Reactor Materials and Components IV
|
| Presentation Title |
Investigating low-dose neutron irradiation-induced softening in PM-HIP Grade 91 Steel |
| Author(s) |
Saquib Bin Habib, Yu Lu, Yaqiao Wu, Donna P. Guillen, David W. Gandy, Janelle P. Wharry |
| On-Site Speaker (Planned) |
Saquib Bin Habib |
| Abstract Scope |
This work studies deformation mechanisms in neutron irradiated Grade 91 steel manufactured by powder metallurgy with hot isostatic pressing (PM-HIP). Grade 91 is a ferritic steel known for its excellent void swelling resistance under irradiation. While Grade 91 is typically cast, PM-HIP fabrication is gaining attention for its higher strength and near net-shape production. However, nanoindentation indicates unusual softening of the PM-HIP Grade 91 alloy with increasing irradiation dose from ~1 to ~3 displacements per atom (dpa) at ~400°C. Focused ion beam (FIB) milling was used to extract transmission electron microscopy (TEM) lamellae from the nanoindentation plastic zone. TEM characterization at intervals of ~250 nm from the indent tip revealed the interaction of dislocation lines with loops. At ~1 dpa, the region nearest the indent is nearly dislocation-free, while dislocation density increases deeper into the plastic zone, suggesting propagation of a strain-hardened front that could explain the higher hardness. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Nuclear Materials, Mechanical Properties, Characterization |