About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Dilute Alloying and Impurity Effects on Phase Transformations
|
| Presentation Title |
Cu-Enabled NiAl Precipitation in a Mn-Stabilized Austenitic Steel |
| Author(s) |
Keith E. Knipling, Edwin Antillon, David Rowenhorst, Patrick Callahan, Colin Stewart |
| On-Site Speaker (Planned) |
Keith E. Knipling |
| Abstract Scope |
Minor alloying additions can fundamentally alter phase stability, transformation pathways, and precipitation behavior in structural alloys. In a Mn-stabilized austenitic steel strengthened by nanoscale NiAl precipitates, Cu additions are essential for precipitation hardening despite comprising only ~3 at.% of the alloy composition. We demonstrate that Cu thermodynamically stabilizes a metastable FCC L1₂ precursor phase that enables homogeneous intragranular NiAl precipitation and is subsequently expelled as the precipitates transform toward equilibrium B2 NiAl. Building on this mechanistic understanding, ongoing work is investigating the use of two-step aging treatments to independently control precipitate number density and volume fraction and dilute Si additions to enhance precipitation kinetics. These results establish dilute alloying additions as a powerful tool for engineering metastable precipitation pathways and microstructural evolution in precipitation-strengthened FCC alloys. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Iron and Steel, ICME, Phase Transformations |