title: Experimental study and thermodynamic modeling of the Al-Co-Cr-Ni system.
abstract: A thermodynamic database for the Al-Co-Cr-Ni system is built via the Calphad method by extrapolating re-assessed ternary subsystems. A minimum number of quaternary parameters are included, which are optimized using experimental phase equilibrium data obtained by electron probe micro-analysis and x-ray diffraction analysis of NiCoCrAlY alloys spanning a wide compositional range, after annealing at 900 °C, 1100 °C and 1200 °C, and water quenching. These temperatures are relevant to oxidation and corrosion resistant MCrAlY coatings, where M corresponds to some combination of nickel and cobalt. Comparisons of calculated and measured phase compositions show excellent agreement for theβ-γequilibrium, and good agreement for three-phaseβ-γ-σandβ-γ-αequilibria. An extensive comparison with existing Ni-base databases (TCNI6, TTNI8, NIST) is presented in terms of phase compositions.
authors.affiliation: Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gheno
authors.affiliation: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Xuan L
authors.initials: XL
authors.lastname: Liu
authors.affiliation: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Greta
authors.initials: G
authors.lastname: Lindwall
authors.affiliation: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Zi-Kui
authors.initials: ZK
authors.lastname: Liu
authors.affiliation: Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Gleeson
keywords: Calphad; MCrAlY; bondcoat; phase compositions; phase equilibrium