Morphology and competitive growth during the development of the parallel lamellar structure by self-seeding in directionally solidified Ti-50Al-4Nb alloy

The non-preferred crystals always take on the tilting primary dendrites along the growth direction and the asymmetric “V”-shape morphology at the solid-liquid interface, which corresponds to the developed second and third dendritic arms at the fore-lateral direction and the degenerated dendritic arms at the back-lateral direction of the tilting primary crystal. The growth morphology above is greatly connected with the growth advantage of the non-preferred crystals during the competitive growth.129