Microstructure and Mechanical Properties of a Cast Intermetallic Ti-46Al-8Ta Alloy

Abstract

Microstructure and mechanical properties of a new cast air-hardenable intermetallic Ti-46Al-8Ta (at.%) alloy are studied. Primary solidification phase, solidification path and high temperature phase equilibria are determined using quenching during directional solidification (QDS) experiments combined with microstructural analysis. Vickers hardness, tensile, compression and creep properties are presented. The effect of short-term high temperature exposure on room temperature (RT) ductility of uncoated specimens is evaluated and discussed. Creep properties such as minimum creep rate, time to 1 % creep deformation, fracture time and creep fracture mechanisms are presented and compared to other TiAl base alloys developed for industrial applications. Long-term high temperature microstructural stability and the effect of ageing on Vickers hardness and RT tensile properties are presented. Based on the achieved experimental results, the potential of this new alloy to fulfill industrial specifications is discussed.