Research on the Spray Granulation Pre-alloyed W-Ni-Fe Ternary Alloy Powder and Densification and Spheroidization by RF Thermal Plasmas

The spheroidization and densification of tungsten-based alloy powder is of great significance to the component properties improvement, such as the strength of powder-fabricated components by additive manufacturing. The effect of radio frequency (RF) thermal plasma treatment on the morphology and porosity of spray granulated pre-alloyed W- Ni- Fe alloy powder were studied. The results show that the 96W-2.5Ni-1.5Fe ternary alloy powder formed by spray granulation has a loose microstructure, part of the powders have internal voids and a rough surface. The comprehensive properties of the spray granulated powder can be significantly improved after RF thermal plasma treatment. The holes and looseness on the surface of spherical powder are alleviated, but a few particles also have some micropores on the surface and in the internal. The Ni and Fe phases between the W grains of the densified and spheroidized particles contain a relatively high content of W element.