Study on preparation technology of spherical TiAl alloy powders used for additive manufacturing

Through optimizing and improving the guide system and atomizer, the spherical TiAl alloy powders with low oxygen content and high fine powder yield were prepared by water-cooled copper crucible vacuum induction melting gas atomizing technology, using the TiAl alloy blocks as the raw materials. In the results, the graphite guide base with good thermal conductivity and the BN ceramic guide core with erosion resistance can not only ensure the heating of guide pipe, but also effectively prevent the erosion of molten metal. The spiral nozzle atomizer moves the atomization point downward, and the position of reflux area is far away from the outlet of guide pipe, which solves the problem of liquid column backflow. The spiral distribution tube can effectively restrain the atomized gas, reduce the kinetic energy loss, and significantly improve the yield of fine powders by more than 20%. The fluidity of the spherical TiAl alloy powders prepared in the experiment is 27.7 s·(50 g)^‒1, the sphericity is more than 90%, and the oxygen incremental is small, which are suitable for the 3D printing and injection molding.