Titanium matrix composites (TMCs) have been extensively evaluated for their potential to replace conventional superalloys in high temperature structural applications, with significant weight-savings while maintaining comparable mechanical properties. New gamma titanium aluminide alloys and an appropriate fiber could offer an improved TMC for use in intermediate temperature applications (400-800 C). The purpose of this investigation is the evaluation of a gamma titanium aluminide alloy with nominal composition Ti-46.5Al-4(Cr, Nb, Ta, B)at.% as a structural material in future aerospace transportation systems, where very light-weight structures are necessary to meet the goals of advanced aerospace programs.Johnson, W. Steven and Weeks, Carrell E.Langley Research CenterMECHANICAL PROPERTIES; STRUCTURAL DESIGN; TITANIUM ALUMINIDES; HYPERSONIC FLIGHT; HEAT RESISTANT ALLOYS; X-43 VEHICLE; TEMPERATURE; FEASIBILITY ANALYSIS; THERMAL PROTECTION; METAL MATRIX COMPOSITES; FAILURE MODES; YIELD STREN