Investigation of as-cast alloys in the Pt–Al–Cr system

Platinum-based alloys are being developed which have microstructures that are analogous to the γ/γ′ microstructure of the nickel-based superalloys. These Pt-based alloys have the potential to be used for high-temperature applications. The ternary Pt–Al–Cr system was investigated as part of the continued development of a thermodynamic database for the Pt–Al–Cr–Ru system. Scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analyses were used to obtain phase equilibria data. The alloys were studied in the as-cast condition. A solidification projection was constructed and a liquidus surface derived. It was concluded that all phase regions were identified correctly since the results were self-consistent. Three ternary phases and 21 ternary invariant reactions were identified.