Fabrication of spherical W–ZrC powder for additive manufacturing by spray granulation combined with plasma spheroidization

In this study, a W–1%ZrC spherical powder for additive manufacturing was successfully fabricated by spray granulation combined with radio frequency (RF) plasma spheroidization. 3 μm tungsten powder and the nano-sized ZrC powder were spray granulated into a porous agglomerated powder and then spheroidized to form a dense spherical powder by RF plasma. Spherical W–ZrC powder with a narrow particle size distribution and a uniform distribution of Zr element was obtained, whose flowability and apparent density was 7.5 s/50g and 9.36 g/cm3, respectively. Furthermore, ZrC enters the tungsten grains after plasma spheroidization, which causes dislocations in the tungsten grain. The spherical W–ZrC composite powder is expected to suppress the crack formation of W parts during the laser powder bed fusion process.