|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||A Strategy to Optimize Local Phase Transformation Strengthening for Next Generation Superalloys
||Timothy Smith, Nikolai Zarkevich, Ashton Egan, Timothy Gabb, John Lawson, Michael Mills
|On-Site Speaker (Planned)
For this study, a new disk superalloy (TSNA-1) specifically designed to take advantage of strengthening atomic-scale dynamic complexions is explored. 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. Findings from this study can help guide researchers to further optimize the LPT strengthening mechanism for future alloy development.
||Phase Transformations, High-Temperature Materials, Characterization