|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||Evolution of Nanoscale Clusters in γ´ Precipitates of a Ni-Al-Ti Model Alloy
||Florian Vogel, Nelia Wanderka, Zoltan Balogh, Patrick Stender, Mohammed Ibrahim, Guido Schmitz, Tatiana Fedorova, John Banhart, Monica Kapoor, Gregory Thompson
|On-Site Speaker (Planned)
Understanding phase separation phenomena enables tailoring microstructures of Ni-based superalloys to achieve improved mechanical properties. In this study we utilize atom probe tomography to clarify the origin of γ particles in ordered (L1<sub>2</sub>) γ´ precipitates in a Ni<sub>86.1</sub>Al<sub>8.5</sub>Ti<sub>5.4</sub> alloy. Particularly, we elucidate the evolution from nanoscaled Ni-rich heterogeneities (Ni-rich clusters) to γ spheres and then γ plates inside γ´ precipitates from the compositional and the thermodynamic point of view. We find that Ni supersaturation of γ´ precipitates is relieved by formation of Ni-rich clusters, which results in an energetically more favorable state, although additional surface is created. Subsequently, the created surface is reduced by coalescence which introduces necking between the Ni-rich clusters and leads to the formation of γ particles. Our results reveal that the phase separation of γ´ precipitates is characterized by different stages with various governing driving forces.
||Planned: A print-only volume