About this Abstract |
Meeting |
2021 TMS Annual Meeting & Exhibition
|
Symposium
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Materials for High Temperature Applications: Next Generation Superalloys and Beyond
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Presentation Title |
Solute Segregation at Intrinsic Stacking Faults in Disordered Face-centered Cubic Ni-Co Solid Solution: First-principles and Thermodynamic Modeling |
Author(s) |
Dongsheng Wen, Longsheng Feng, Yunzhi Wang, Michael S. Titus |
On-Site Speaker (Planned) |
Dongsheng Wen |
Abstract Scope |
Displacive-diffusive phase transformations that involve complex shearing, reordering, and diffusion mechanisms in the L12-gamma’ phase during high temperature creep have recently been observed in Ni-, NiCo-, and Co-based superalloys and have been correlated with high temperature mechanical properties of these alloys. To better understand these processes, we have determined the equilibrium intrinsic stacking fault composition, unsegregated stacking fault energy (SFE), and segregated SFE in the disordered face-centered cubic Ni-Co solid solution as a function of composition and temperature. Comparisons to experiments show that the segregated SFE, calculated via first-principles, matches within 5% of experimentally-determined SFEs. Furthermore, we found that the predicted segregation enthalpy matches well with bulk thermodynamic calculations. The predicted segregation energy is also used to evaluate thermodynamic properties of the stacking fault and then compared to its bulk counterpart. The implications for improving high temperature mechanical properties will be presented, and new alloy design strategies will be discussed. |
Proceedings Inclusion? |
Planned: |
Keywords |
Modeling and Simulation, High-Temperature Materials, Phase Transformations |