Decomposition Behavior and Strengthening Mechanism of Ti-TiO2 Material in Selective Laser Melting Process

This study investigated the fabrication of a strengthened Ti-TiO 2 material with adding 0.5 wt.% TiO 2 nanoparticles via selective laser melting process in comparison with CP-Ti. Through the process parameters optimized by response surface methodology, the Ti-TiO 2 material fabricated by SLM showed remarkable tensile strength of 800.6 MPa and elongation of 14%, as compared to the fabricated CP-Ti with tensile strength of 594.0 MPa and elongation of 21%. The x-ray diffraction patterns of fabricated specimens showed the expansion of the hcp -Ti lattice along the c -axis due to dissolved oxygen atoms from the decomposition of TiO 2 nanoparticles. The microstructure analysis observed remains of incompletely decomposed TiO 2 and TiO phases in SLMed Ti-TiO 2 material, which was distinguished from former studies. Consequently, the decomposition behavior of added TiO 2 nanoparticles associated with the dissolved oxygen in the Ti-matrix during the SLM process was discussed. Based on the evaluation of both the solution effect of oxygen atoms and the reinforcing effect of undecomposed nanoparticles, the dissolved oxygen from decomposed TiO 2 was considered the primary factor in the intensified strength of SLMed Ti-TiO 2 material. These results could offer novel insights into the additive manufacturing of high-strength and biocompatible titanium alloy via the SLM process.