射频等离子体球化钨粉的选区激光熔化成形研究

以不规则的钨粉为原材料,采用射频等离子体球化技术制备了球形钨粉,重点研究了选区激光熔化制造纯钨零件,系统研究了工艺参数(激光功率、扫描速度)对制备的纯钨样品致密化、显微组织、显微硬度和压缩性能的影响,从而反馈指导钨粉球化工艺参数的优化。结果表明：球化后钨粉形状规则且球化率高于98%,钨粉的振实密度和松装密度增大,流动性增强。同时球化后的钨粉具有良好的选区激光熔化适用性,打印样品件的致密度在84%-95.6%之间。研究发现,随 激光功率的增大,打印件的致密度、显微硬度和抗压强度呈先上升后下降的趋势,裂纹和孔洞减少。随着扫描速度的增大,打印件的致密度和硬度降低,裂纹增多。因此探究合适的打印参数对钨粉的选区激光熔化成形有着重要意义。

RF Plasma Spheroidization of Tungsten Powder for Selective Laser Melting

Using irregular tungsten powder as the raw material, spherical tungsten powder was prepared by radio frequency plasma spheroidization technique in this study. It mainly focused on the pure tungsten parts fabricated by the selective laser melting. The study systematically investigated the impact of process parameters (including laser power and scanning speed) on the densification, microstructure, microhardness and compressive properties of the pure tungsten samples. Results showed that after being spheroidized, the tungsten powder had regular shape and its spheroidization rate reached more than 98%. Besides, the tap density and loose density of the tungsten powder were increased and its flowability was also improved. Meanwhile, the spheroidized tungsten powder was well-adapted to selective laser melting, with the density of printed samples between 84% to 95.6%. The study also found that with the increase of laser power, the density, microhardness and compressive strength of printed samples increased first and then decreased, while their cracks and holes decreased. Furthermore, with the increase in the scanning speed, the density and hardness of the printed samples reduced while the amount of cracks increased. Therefore, it is of great significance for the selective laser melting of tungsten powder to explore the appropriate printing parameters.