Microstructure and mechanical property of directionally solidified Ti-46Al-0.5W-0.5Si alloys with and without Gd

The microstructure and mechanical properties of directionally solidified Ti-46Al-0.5W-0.5Si with and without Gd have been investigated. Ti-46Al-0.5W-0.5Si consists of a nearly fully lamellar (α2/γ) structure with γ/Ti5Si3 eutectic in the interdendritic regions, small Ti5Si3 particles at the α2/γ interfaces and some W-rich B2 phase in the dendrites. The addition of Gd brings about the formation of Gd2TiO5 and helps grain refine, thus improving the strength of the alloy. However, the texture of the ingots leads to a strong dependence of the strength on the loading axis.