About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
|
Symposium
|
Tackling Structural Materials Challenges for Advanced Nuclear Reactors
|
Presentation Title |
Progress Toward Additive Manufacturing of Ferritic-martensitic, In situ Tempered Steels for Nuclear Applications |
Author(s) |
Calvin R. Lear, Todd Steckley, Mehmet Topsakal, Simerjeet Gill, Thomas Lienert, Stuart Maloy |
On-Site Speaker (Planned) |
Calvin R. Lear |
Abstract Scope |
Although laser-directed energy deposition (L-DED) offers potentially significant cost savings for metallic reactor components (tooling independence, building to near final shape), L-DED microstructures are not ideal for some promising structural materials. Wrought Gr 91 steel, for example, is both radiation tolerant and resistant to high-temperature creep, while L-DED Gr 91 is mostly fine martensite and extremely brittle. We proposed to remedy this deficiency without a traditional tempering (undesirable due to cost and large components) by adapting principles of multi-pass welding used on boilers and pressure vessels to L-DED. Build parameters were tailored such that prior (lower) layers are tempered by excess heat from later (upper) beads. This process results in an inner Gr 91 component with suitable metallurgical properties. Here, we explore the impact of build pre-heat (~25, 90, 200, and 400 °C) through microstructural characterization using EBSD and through phase analysis using high-energy X-ray diffraction at NSLS-II. |