The recycling of selective laser melting medical Ti6Al4V powder and its impact on forming properties

Recycling of metal powder constitutes an important means to save costs and shorten the preparation cycle in the selective laser melting process. However, the influence of the recycling times on the physical and chemical properties of the powder as well as the performance of the formed parts remain unclear. This article investigated the impact of different recycling times on the particle size distribution, morphology, chemical composition, fluidity, and other physical and chemical properties of the titanium alloy powder. It also characterizes and analyzes the microstructure and mechanical properties of the formed samples. The research findings indicate that after 30 recycling times, the particle size distribution becomes more concentrated, the particle size increases, the adhesion and agglomeration of the particles decrease. The contents of aluminum and oxygen in the chemical composition change, the fluidity and sphericity rate of the powder fluctuate slightly. The bulk density and tapped density increase marginally. As the number of recycling times increases, the microstructure of the formed samples is not affected, consisting of fine lamellar α+β phases. The density and hardness values remain stable, the tensile strength improves, and the fracture characteristics remain unchanged.