基于Laval喷嘴的层流气雾化法工艺参数探索及粉末性能研究

基于Laval喷嘴的层流气雾化技术可以高效制备高性能金属粉末，但目前对这种技术的各项工艺参数及粉末性能尚未有系统性研究。本工作使用基于Laval喷嘴的层流气雾化制粉设备制备了AlSi10Mg合金粉末，同时使用传统分析方法和X射线计算机断层扫描技术分别研究了雾化气体压力以及导流管内径对粉末整体形貌、三维形貌、球形度、粒度分布、物理性能及内部缺陷的影响，并结合数值模拟进行机理性解释。结果表明，基于Laval喷嘴的层流气雾化技术制备的AlSi10Mg粉末性能较好，由于在较高的雾化气体压力和较窄的导流管内径条件下气液流量比更高，金属熔体更易发生破碎，故制备的粉末球形度更好，粒度分布较窄，细粉收得率可接近50%，不规则粉末及空心粉较少。

Study on process parameters and powder properties of laminar gas atomization based on Laval nozzle

Laminar gas atomization technology based on Laval nozzle can efficiently prepare high-performance metal powders, but there is no systematic research on the process parameters and powder properties of this technology. In this paper, AlSi10Mg alloy powders were prepared by laminar gas atomization equipment based on Laval nozzle. At the same time, the effects of atomization gas pressure and tube inner diameter on the overall morphology, three-dimensional morphology, sphericity, particle size distribution, physical properties and internal defects of the powders were studied by traditional analysis methods and X-ray computed tomography technology. Combined with the numerical simulation of single-phase gas flow field and gas-liquid two-phase flow, the influence of process parameters on powder properties is explained. The results show that the performance of AlSi10Mg powders prepared by laminar gas atomization technology based on Laval nozzle is better than traditional gas atomization methods. Due to the higher gas pressure and narrow tube inner diameter, the gas-to-melt mass flow rate is higher, and the metal melt is more likely to be broken. Therefore, the powders have better sphericity, narrow particle size distribution, high fine powder yield of nearly 50%, and less irregular powders and hollow powders, The overall performance of AlSi10Mg alloy powders prepared by laminar gas atomization can meet the requirements of additive manufacturing.