Microstructure evolution of directionally solidified Ti-46Al-0.5W-0.5Si alloy

► Solidification path of the alloy is L→L+α→Ti5Si3+α→Ti5Si3+[α2+γ]. ► W segregates in α dendritic cores and Si enriches in interdendritic regions. ► Ti5Si3 phase distributes in the grain boundaries. ► λ1 and λL decreases with increasing growth rate. ► PGD of the α phase changes with increasing growth rate.