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A. Redermeier, E. Povoden-Karadeniz, E. Kozeschnik:
"Thermodynamic description of TCP phases in commercial single crystal Ni-base superalloys with special emphasis on the P-phase";
Talk: Modelling and Simulation of Superalloys 2017, Bochum, Deutschland; 2017-03-29 - 2017-03-31.

To enhance the high-temperature creep properties of Ni-base superalloys, an increasing amount of refractory metals, such as Mo, Re and W, is added. Unfortunately, these elements also promote the occurrence of topologically close-packed (TCP) structures, which deteriorate the mechanical properties of the superalloys. A variety of competing phases has been observed at typical service temperatures of modern Ni-base superalloys, but their relative thermodynamic stabilities are in part still in question. This makes the development of a suitable, comprehensive modeling base for theoretic predictions of their evolution during processing and service difficult. This work is focused on the thermodynamic description of the P-phase. For this, we utilize information from experimental phase diagrams and reported phase stabilities in industrial multicomponent Ni-base superalloys in combination with thermodynamic data evaluated by first-principles calculations. With this combined approach we get a deeper understanding of the occurrence of the P-phase in Ni-base superalloys.

Ni-base superalloys, TCP phase, P-phase