增材制造用球形TiAl合金粉末制备工艺研究

以TiAl合金块为原料，利用水冷铜坩埚真空感应熔炼气雾化技术制粉，通过对导流系统和雾化器的优化改进，制备出氧含量低、细粉收率高的球形TiAl合金粉末。结果表明，将导热性好的石墨导流基座和耐冲刷的BN材质陶瓷导流内芯配合使用，既可以保证导流管加热，也可以有效阻止金属熔液的冲刷；螺旋喷管雾化器使雾化点下移，回流区位置远离导流管出口，解决了液柱反流的问题。螺旋分布管能够有效约束雾化气体，动能损失小，能够显著提高细粉收率达20%以上。实验制备的球形TiAl合金粉末流动性为27.7 s·(50 g)?1]，球形度＞90%，粉末氧增量小，适用于3D打印和注射成型工艺用粉。

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.