Search

Scanning electron microscopes (SEM) and transmission electron microscopes (TEM) were employed to investigate the topologically close-packed (TCP) phases in an experimental nickel base single crystal superalloy. Orientation relationships between P phase and matrix were found as (010) P //(1 1 ‾ 1) γ and [201] P //[110] γ , in which atomic arrangement of P phase obtains the optimal matching with that of γ/γ' matrix and the semi-coherent interface forms, achieving the lower interface energy. The elemental composition, atomic arrangement of low index planes and the atomic attachment of P phase with matrix were analyzed in detail to investigate the atomic scale structure of the fast-growing semi-coherent interface and its effects on precipitate growth. Finally, the nucleation of P phase was discussed. • μ and P phase were characterized by electron microscopes. • HRTEM micrographs and orientation relationships imply the semi-coherent P/γ interface. • Atomic attachment of P phase with matrix was discussed. • The nucleation of P phase was discussed. [ABSTRACT FROM AUTHOR]