Additively Manufactured Biomedical Ti-15Mo Alloy with Triply Periodical Minimal Surfaces and Functional Surface Modification

Ti and Ti alloys are being widely used as bone tissue repair materials. Progress on mechanical properties and bio-functionality is required for their applications due to the large difference in elastic modulus between bone and Ti implants and the fact that the Ti materials themselves are biologically inert. In this work, a low-modulus, β-phase Ti-15Mo alloy based on a triply periodical minimal surfaces (TPMS) structure was fabricated using a Powder Bed Fusion-Laser Beam (PBF-LB) under optimized printing parameters into implant samples with controllable porous structures. The selection of TPMS, lattice unit cell size, and relative density was based on a combination of mechanical properties and cytocompatibility. Surface modifications were used to further impart antibacterial, antioxidant, and osteogenesis properties to the implants. Broad-spectrum antibacterial Ag, antioxidant tannic acid (TA), and highly stable fluorinated hydroxyapatite ((F)HA) were applied as an advanced coating on a microporous TiO2 surface modification layer formed by micro-arc oxidation. Ultimately, porous Ti-15Mo implant samples with a biofunctional coating were obtained with Young’s modulus 15–50 GPa, a yield strength of approximately 100 MPa, and good cytocompatibility, hemocompatibility, and bactericidal effects. This study provides a systematic scheme for the preparation and surface modification of β Ti alloy implants for subsequent studies.