Powder bed fusion manufacturing of beta-type titanium alloys for biomedical implant applications: A review

Thanks to many fascinating properties, such as high mechanical properties, good corrosion resistance, and excellent biocompatibility, beta-type Ti alloys are frequently employed as biomedical implants. In recent decades, rapidly developed powder bed fusion (PBF) technologies have become new methods for fabricating beta-type Ti alloys. This article reviews the recent advances and insightful perspectives on the feedstock powder characteristics (e.g., pre-alloyed powder and elemental powder mixtures), microstructure, mechanical properties, and corrosion behavior of PBF-produced beta-type Ti alloys in the forms of bulk solid parts and lattice structures. As reviewed, PBF-produced bulk beta-type Ti alloys exhibit higher strength than their conventional counterparts, accompanying with slight decrease in the maximum deformation strain. The corrosion behavior of PBF-produced bulk beta-type Ti alloys with the identical corresponding chemical compositions is related to their phase constituents in microstructure, which results from the fabrication methods or processing procedures. Additionally, PBF-produced bulk beta-type Ti alloys still have higher elastic moduli than the human bones. Hence, with the assistance of PBF technologies, lattice structures of beta-type Ti alloys with lower and controllable moduli are developed to obtain reduced their elastic moduli. For biomedical implant applications, PBF-produced lattice structures of beta-type Ti alloys with multifunctional coatings may become promising materials in the future. Nevertheless, the investigations on the PBF-produced beta-type Ti alloys for biomedical implant applications are hitherto still in the initial stage.