Ultra-high temperature intermetallics for the third millennium

Nickel-base superalloys are hugely successful materials, however they are a pproaching the limit of their high temperature capability. There is a prese nt and future need for ultra-high temperature alloys which are strong at te mperatures at least 200 degreesC above the maximum operating temperature of nickel-base superalloys. We are attempting to design an ultra-high tempera ture alloy based on platinum. Despite its high cost and density such an all oy might have applications in static components for gas turbines, in rocket s, glass manufacture and elsewhere. In order to achieve high-temperature st rength we are attempting to mimic a nickel-base superalloy structure but. u sing an f.c.c. platinum matrix strengthened by coherent platinum-base inter metallic particles with the Lit structure. Microstructural and phase diagra m results are given for the Pt-Zr and Pt-Rh-Zr systems, both of which are s hown to exhibit low-misfit f.c.c./Ll(2) microstructures. (C) 2000 Elsevier Science Ltd. All rights reserved.