|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Gamma (FCC)/Gamma-Prime (L12) Co-Based Superalloys II
||Thermodynamics and Kinetics of L12-containing Co-base Superalloys from First-Principles
||Robert K. Rhein, Tresa Pollock, Anton Van der Ven
|On-Site Speaker (Planned)
||Robert K. Rhein
L12-containing Co-base superalloys have been shown to have high-temperature creep properties that are comparable to second generation Ni-base superalloys. Thermomechanical stability of the L12 precipitate phase is critical in the design of these alloys. Electronic structure calculations have been used as the foundation for the construction of a finite temperature thermodynamic description of the Co-Al- W system from first principles. A cluster expansion technique has been used to fit the formation energies of several unique configurations of fcc, bcc, and hcp Co-Al- W structures. Grand canonical Monte Carlo simulations have been performed on these cluster expansions in order to assess the effects of configurational entropy at finite temperature. Vibrational entropy of selected structures has also been calculated. Free energy surfaces incorporating these entropic effects have been constructed and the implications for high-temperature phase stability and kinetics will be discussed.