Numerical study of convection-induced peritectic macro-segregation effect at the directional counter-gravity solidification of Ti-46Al-8Nb alloy

► Specific centerline segregation is firstly observed in directionally solidified TiAl-Nb ingots. ► Reasons of this effect are hydrodynamics; heat- and mass transfer of rejected Al into melt. ► Primary Al segregation appearance ahead of growth interface is convection-induced. ► Peritectic transformation of Al-enriched axial “spindle” area follows afterwards in solid. ► Solidification conditions have been optimized numerically to avoid undesirable segregation.