Cost-effective preparation of high-purity spherical Ti-6Al-4V powder for additive manufacturing via hydrogen decrepitation and laser spheroidization

Spherical powders are the primary feedstock materials used in additive manufacturing. Currently, a significant challenge in advancing additive manufacturing technology is the achievement of cost-effective production of high-quality powders. In this study, we propose a novel method that utilizes low-cost TiH2 powder to induce refinement and purification through coaxial powder feeding and a laser heating-induced hydrogen decrepitation effect. The results show that the prepared powder exhibit excellent properties such as high purity, high sphericity, and fine particle size. The particle size distribution was significantly reduced from 101 to 240 mu m to 10-55 mu m, and the spheroidization ratio exceeded 99 %. Additionally, the cost of prepared Ti-6Al-4V powder is comparable to that of TiH2 powder, approximately 1/8th of atomization costs. The spheroidized Ti-6Al-4V powder consists of alpha/alpha' Ti and twinned structures. Notably, the dehydrogenation process had a significant impact on the removal of impurities from the powder, where the generated impurities were absorbed by the nanoparticle, resulting in the formation of cores consisting of alpha 2-Ti3Al and gamma-TiAl phases and shell structures comprised of oxides and carbides. In conclusion, this method demonstrates that laser spheroidization of TiH2 powders is an effective and cost-efficient strategy for preparing high-quality spherical titanium alloy powders, offering new possibilities for advancing additive manufacturing technology.