About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
|
| Symposium
|
Alloy Phase Transformations at Elevated Temperatures
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| Presentation Title |
Heterogenous Nucleation of γ' precipitates at Annealing Twin Boundaries in Superalloys: A phase field study. |
| Author(s) |
Vignesh Karunakaran, Longsheng Feng, Semanti Mukhopadhyay, Hariharan Sriram, Fei Xue, Emmanuelle Marquis, Michael Mills, Yunzhi Wang |
| On-Site Speaker (Planned) |
Vignesh Karunakaran |
| Abstract Scope |
High temperature properties in Ni-based superalloys such as creep, fatigue are strongly influenced by their two-phase γ/γ′ microstructure,which could be altered by presence of defects like grain boundaries (GBs) and annealing twin boundaries (ATBs). Recent experimental observations revealed various γ′ precipitation behavior in different Ni-based superalloys towards ATBs,including preferential, non-selective, and avoidance tendencies. Furthermore,for preferential case, γ′ prefer to nucleate at ATBs over random high angle GBs. Since local stress states and dislocation activities during deformation are altered by presence of ATBs and ATB-precipitates,it is important to understand how γ′ interact with ATBs during precipitation in contrast to nucleation at GBs. The current study analyses critical factors contributing to nucleation of γ′ at ATBs and reason for preference over nucleation at GBs. The effects of undercooling, interfacial, ATB and GB energies, elastic strain energy on the nucleation and growth behavior of γ′ at ATBs are documented using phase field simulations. |