Interaction between γ-TiAl alloy and zirconia

TiAl alloys are promising high-temperature structural materials for a wide range of applications such as aerospace, marine and automobile parts owing to their low density, high strength and creep resistance . A range of manufacturing processes have been successfully developed for utilization of these alloys. Among these processes, investment casting is the optimal process because of its low cost, mass-production and high efficiency. However, the main limitation of investment casting for titanium alloys is the chemical reaction between molten titanium and molding materials at high temperature. Many researchers have investigated the mechanisms of the interfacial reactions. Saha [4] and Suzuki [5] proposed that the interfacial reaction is characterized by the exchange of oxygen between molten titanium and mold materials and the generation of gaseous oxides of titanium. Zhou Yanbang, Degawa and Holcombe found that the substitution reaction takes place between titanium melt and ceramic crucible by analyzing the reaction between molten titanium and ceramic crucible. Although extensive studies have been reported, the interfacial reaction between TiAl and zirconia has not been fully elucidated to date. In this paper, to understand the mechanism of the interfacial reactions, the microstructure of the interface between TiAl alloy and Zirconia is investigated using SEM and EDS.