The precipitation and effect of topologically close-packed phases in Ni-based single crystal superalloys

The precipitation of topologically close-packed (TCP) phases is the result of microstructure instabilities of Ni-based superalloys. This review seeks to comprehensively collate all the available information on TCP phases in SX superalloys based on the latest findings. First, the thermodynamics and kinetics of the TCP phase precipitation are introduced. Meanwhile, the morphology, composition and orientation of TCP phases and their sequential transformation are summarized in detail. Further, the factors affecting the precipitation of these phases are sorted out. Besides, the proposed damage mechanisms of TCP phases are listed. Finally, several control and prediction methods of the TCP phase precipitation are reviewed, so the alloy designer can better balance the relationship between microstructure stabilities and properties of the superalloy. & COPY; 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.