Experimental study and thermodynamic modeling of the Al–Co–Cr–Ni system. Issue 5 (21st September 2015)

• Record Type: Journal Article
• Authors: Gheno, Thomas; Liu, Xuan L; Lindwall, Greta; Liu, Zi-Kui; Gleeson, Brian
• Is Part Of: Science and technology of advanced materials. Volume 16:Issue 5(2015)
• Publication Date: 2015-09-21
• Subjects: bondcoat -- phase compositions -- phase equilibrium -- Calphad -- MCrAlY; Materials -- Technological innovations -- Periodicals; 620.112
• DOI: 10.1088/1468-6996/16/5/055001
• Languages: English
• ISSNs: 1468-6996

Abstract

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 the β – γ equilibrium, and good agreement for three-phase β – γ – σ and β – γ – α equilibria. An extensive comparison with existing Ni-base databases (TCNI6, TTNI8, NIST) is presented in terms of phase compositions.