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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.

The spherical Ti‒1Al‒8V‒5Fe alloy (Ti185) powders used for the additive manufacturing were prepared by plasma rotating electrode atomization (PREP), using the high temperature forged Ti185 rods with the diameter of 100 mm as the electrode bar, using the Ti185 alloy ingots without “βspots” prepared by vacuum consumable arc melting as the raw materials. The properties of the Ti185 powders were characterized by vibration sieving, scanning electron microscope (SEM), and X-ray diffraction (XRD). In the results, the particle size distribution of the Ti185 powders is wide, mainly in the range of 44~150 μm. The powder yield with the particle size less than 44 μm is 11.6%. The oxygen content of the powders (mass fraction) is less than 0.14%. The powder fluidity with the particle size less than 150 μm is 24.79 [s∙(50 g)‒1], the bulk density is 2.79g∙cm‒3, and the tap density is 2.99 g∙cm‒3. The Ti185 powders are composed of β phase due to the rapidly cooling during the PREP process. The powders exhibit the high sphericity without the satellite powders. The powders with the particle size larger than 124 μm show the cellular dendrite structure with the small amount of rough and uneven micro pores on the surface of powders. The internal organization of the powders shows the characteristics of multi-point nucleation with the cellular structure and coarse grains after the rapid solidification. With the decrease of particle size and the increase of cooling rate, the cellular dendrite structure on the surface of powders decreases gradually, showing the smooth surface for the powder particle size less than 44 μm. Meanwhile the internal organization of the powders shows a radial growth trend and significant refinement.