Directional solidification of TiAl alloys using a polycrystalline seed
抽拉速率对Ti-43Al-3Si合金籽晶法定向凝固组织的影响

Directional solidification (DS) of Ti-46Al and Ti-43Al-3Si alloys using a polycrystalline seed material of Ti-43Al-3Si by self-made EMCS experimental apparatus with wide range of velocity has been studied. Successful DS ingots were obtained with fully lamellar microstructure parallel to longitudinal axis when the growth rates increased from 60 to 120mm/h. The ingot grown at 60mm/h exhibited typical lamellar microstructure aligned along the growth direction from the seed crystal up to the end part of ingot. On the contrary, as the growth rate increased, the orientation of lamellar microstructure changed beyond the transition point.