| Abstract: | Directional solidification experiments were carried out on Al-4wt%Cu alloy under different withdrawal velocities. It is showed that the primary dendrite arm spacing decreases with increasing withdrawal velocity which is rapid. The solid/liquid interface of dendrite is planar-convex-planar-convex, and it is reinforced first and then weakened and finally almost faded. Dendrite tip temperature is also first increased and then decreased with increasing withdrawal velocity. The KGT model and non-equilibrium effect were used to research the dendrite tip temperature, tip undercooling and composition. This explains the change of dendrite interface morphology well. |
