EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Much attention has been given over the last decade to TiAl intermetallics due to their low density, high specific strength and relatively good resistance to oxidation at service conditions. These alloys are considered as structural materials in new generation energy-conversion systems that expectedly increase their power efficiency and ecological compatibility owing to reduced component weight. Nevertheless, studies are going on developing new alloys to improve the inherent poor ductility of titanium aluminides at ambient temperatures, while increasing their mechanical properties at higher temperatures up to 800°C. Two major approaches have been considered to improve room temperature ductility and high temperature resistance: microstructure optimization through thermomechanical treatment and subsequent heat treatments, addition of appropriate alloying elements. These alloying elements, such as beta-stabilizers, or even elements of the III and IV columns of the periodic table (C, Si and B, in small amounts) are renowned to improve high temperature behavior. In the present work, various ingots were prepared by using an arc melting furnace. First, the effect of the alloying elements on the solidification route by using Scheil calculations was studied, and then the phase stability and microstructure of various alloys were investigated and compared, focusing on the stability of beta phase.