About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Phase Transformations and Microstructural Evolution
|
| Presentation Title |
Enhancing Creep Strength of Superalloys Utilizing Local Phase Transformation Strengthening and CALPHAD Based Design |
| Author(s) |
Ashton J. Egan, Longsheng Feng, Christopher Zenk, Yunzhi Wang, Michael Mills, Steffen Neumeier, Erdmann Spiecker, Mathias Göken |
| On-Site Speaker (Planned) |
Ashton J. Egan |
| Abstract Scope |
Deformation in the intermediate temperature regime of Co- and Ni-based superalloys is dominated by shear of planar defects, whereby diffusion and reordering drive shearing. Local Phase Transformation (LPT) occurs at these defects (χ-SISFs/microtwins and η-SESFs), preventing rapid strain accumulation by limiting further shearing partial dislocations. A CALPHAD-based design approach was implemented leveraging the LPT strengthening effect; for Ni-based systems η-LPT has improved a polycrystalline alloy to the performance of traditionally used single crystals. Here, Co-based superalloys were created by aggressively promoting both η and χ-LPT, the latter being extremely effective in preventing microtwin thickening, with the goal of creating an optimized alloy for polycrystalline response. Single crystalline analogs of several alloys were cast to study fundamental deformation and effectiveness of LPT under specific compressive loading conditions, namely along [001] and [011]. Atomic resolution HR-STEM observations of deformation substructures allowed for compositional analysis of LPT and assessment of its effectiveness. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Temperature Materials, Mechanical Properties, Phase Transformations |