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喷嘴进气方式对3D打印用GTD222高温合金粉末性能的影响

Influence of nozzle gas inlets on properties of GTD222 superalloy powders for additive manufacturing

  • 摘要: 利用真空熔炼紧耦合气雾化制粉技术制备了3D打印用GTD222高温合金粉末,研究了喷嘴进气方式对粉末化学成分、粒度分布、球形度、流动性、松装密度及表面形貌等特性的影响。结果表明,采用外直内切喷嘴结构,加强了喷嘴出口处的抽吸效应,有利于提升气雾化过程的稳定性;采用切向进气方式增强了气体剪切作用效果,有利于提升细粉(15~53 μm)收得率。在过热度200 ℃、雾化压力3 MPa的工艺参数下,制备的粉末氧含量(质量分数)低于0.02%,中位径57.98 μm,球形度0.77,流动性26.15 g/(50 s),松装密度4.63 g/cm3,满足金属3D打印技术对粉末材料性能的要求。

     

    Abstract: The GTD222 superalloy powders for the additive manufacturing were prepared by the vacuum inert gas atomization (VIGA) with the close-coupled nozzle system in this paper. The effects of nozzle gas inlets on the chemical composition, particle size distribution, sphericility, fluidity, loose packed density, and surface morphology of the GTD222 superalloy powders were studied. The results show that, using the nozzle with an “outer straight inner tangent” structure enhances the suction effect of the nozzle and improves the stability of the closed-coupled gas atomization process. In addition, the tangent inlet system enhances the gas shear effect, therefore improves the yield of the fine powders (15~53 μm). The optimized process parameters are found in the conditions of 200 ℃ superheat and 3 MPa atomization pressure. The oxygen mass fraction of the powders prepared in the optimized conditions is 0.02%, the medium diameter is 57.98 μm, the degree of sphericility is 0.77, the fluidity is 26.15 g/(50 s), and the loose packed density is 4.63 g/cm3, which meet the requirements of the metal additive manufacturing technology.

     

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