Ultra-high temperature intermetallics for the third millennium

Nickel-base superalloys are hugely successful materials, however they are approaching the limit of their high temperature capability. There is a present and future need for ultra-high temperature alloys which are strong at temperatures at least 200°C above the maximum operating temperature of nickel-base superalloys. We are attempting to design an ultra-high temperature alloy based on platinum. Despite its high cost and density such an alloy might have applications in static components for gas turbines, in rockets, glass manufacture and elsewhere. In order to achieve high-temperature strength we are attempting to mimic a nickel-base superalloy structure but using an f.c.c. platinum matrix strengthened by coherent platinum-base intermetallic particles with the L12 structure. Microstructural and phase diagram results are given for the Pt–Zr and Pt–Rh–Zr systems, both of which are shown to exhibit low-misfit f.c.c./L12 microstructures.