Effects of solidification parameters on the growth direction of α phase in directionally solidified Ti-49A1 alloy

Growth directions (GD) variation of a phase in Ti-49A1 (at.%) alloy with solidification parameters were studied by using directional solidification technology. GD of the primary phase (alpha phase) changed with growth rate (V) and temperature gradient (G). Evolutions of theta (the angle between the preferred growth direction (PG) and heat flow direction (HD) and Psi (the angle between GD and HD) with V and G are presented. By controlling the solidification parameters accurately, the grains of a solidified TiAl alloy can grow with <11<(2)over bar>0> direction or close to this direction during directional solidification, which is beneficial to the lamellar orientation control of TiAl alloys. For present experimental conditions, the feasible solidification condition for the lamellar orientation control of TiAl alloy by the seeding technology is: V = 10 mu m/s similar to 20 mu m/s and G = 10 K/mm similar to 12.1 K/mm.