CaO-assisted deoxidation enabling the production of low-oxygen spherical Ti-6Al-4V powder

Spherical Ti-6Al-4V alloy powder is a critical feedstock for additive manufacturing, and there is an increasing demand for low-oxygen powders produced using sustainable methods. In this study, fine spherical Ti-6Al-4V powder with a particle size of 15–53 μm was deoxidized via calciothermic reduction, utilizing CaO as a dispersant to suppress powder sintering. The effects of deoxidation parameters on oxygen content and recovery yield were systematically investigated, and the deoxidation mechanism and dispersion behavior were elucidated. The results show that optimal CaO addition effectively prevents direct interparticle contact, thereby inhibiting agglomeration and sintering during deoxidation and significantly enhancing powder recovery yield. Under conditions of 1000°C, 2 h, m CaO/Ti-6Al-4V  = 1, and m Ca/Ti-6Al-4V  = 0.09, the deoxidized powder retained its spherical morphology without observable sintering, exhibiting an oxygen content of 780 ppm and a recovery yield of 92%. The key powder characteristics — flowability (31 s/50 g) and apparent density (2.37 g/cm 3 ) — closely match the typical values reported for commercial LPBF feedstocks.