Fabrication of spherical MoNbTaWZr refractory high-entropy powders by spray granulation combined with plasma spheroidization

To obtain spherical MoNbTaWZr powders, porous agglomerated MoNbTaWZr particles prepared by spray granulation were subsequently processed by plasma spheroidization. The microstructure, morphology, particle size distribution, purity and property of each step during process were systematically investigated. Results show that the obtained spherical MoNbTaWZr powder has dense structure, smooth surface, and good sphericity in shape. It also has narrow particle size distribution, while D10, D50, D90 and Dav were 32.0 µm, 42.3 µm, 56.0 µm and 43.2 µm, respectively. The powder has a high purity, and the concentration of oxygen, hydrogen, carbon, and nitrogen were all at ppm. In addition, excellent flowability (8.89 s/50 g) and apparent density (7.27 g/cm3) are benefit from high spheroidization ratio (98.4 %) and dense structure. The spherical powder also exhibits a high nano-hardness due to solid solution strengthening and refinement in dendritic structures.