About this Abstract |
Meeting |
Superalloys 2024
|
Symposium
|
Superalloys 2024
|
Presentation Title |
Optimizing Local Phase Transformation in Ni-based Superalloys Utilizing Thermodynamically Driven Design Framework and Multiscale Characterization |
Author(s) |
Ashton J. Egan, Longsheng Feng, Timothy Smith, Yunzhi Wang, Michael Mills |
On-Site Speaker (Planned) |
Ashton J. Egan |
Abstract Scope |
Superalloys are inherently complex alloys to design due to their multicomponent nature; designing alloys to take advantage of the newly discovered Local Phase Transformation (LPT) strengthening creates constraints on alloy composition beyond the conventional considerations for polycrystalline, precipitate-strengthened microstructures. The basis for design is precipitation of ÷/ç on superlattice stacking faults and microtwins while remaining thermodynamically inaccessible to form in bulk. This approach to LPT strengthening has now been demonstrated by optimizing ç-LPT in an empirically designed alloy, NA1, the performance of which is shown here by testing [001] oriented single crystals at several conditions. Computationally designed alloy, NA6, in polycrystalline form, was shown to perform similarly to single crystalline NA1 at 760 °C 552 MPa and outperform single crystal CMSX-4 as well as all LPT-strengthened polycrystalline alloys at this temperature. The deformation substructure of NA6 was investigated via HR-STEM, showing both ç-LPT at SESF as well as ÷-LPT at microtwins. Compositions of these LPT were elucidated using atomic resolution energy dispersive X-ray spectroscopy and compared to LPT compositions in relevant alloys and discussed considering recent studies on fault propagation velocities. |
Proceedings Inclusion? |
Definite: At-meeting proceedings |