| About this Abstract |
| Meeting |
MS&T22: Materials Science & Technology
|
| Symposium
|
Alloy Phase Transformations at Elevated Temperatures
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| Presentation Title |
The Optimization of Local Phase Transformation Strengthening in Next Generation Superalloys |
| Author(s) |
Timothy Smith, Nikolai Zarkevich, Mikhail Mendelev, Valery Borovikov, Ashton Egan, Timothy Gabb, John Lawson, Michael Mills |
| On-Site Speaker (Planned) |
Timothy Smith |
| Abstract Scope |
NASA is currently developing novel disk superalloys (TSNA-#) that leverage a recently discovered phase transformation strengthening mechanism. This local phase transformation (LPT) strengthening provided TSNA-1 with a 3x improvement in creep strength over similar disk superalloys and comparable strength compared to the single crystal blade alloy CMSX-4 at 760 °C. Through ultra-high-resolution chemical mapping of the stacking faults induced by creep deformation, it was discovered that the improvement in creep strength was a result of atomic-scale η (D024) and χ (D019) formation along superlattice stacking faults. To understand these results, the energy differences between the L12 and competing D024 and D019 stacking fault structures and their dependence on composition were then computed from first principles using density functional theory and molecular dynamic models. Other properties beyond creep strength will also be discussed with relations to these atomic scale deformation processes. |