Microstructural evolution, corrosion behavior and cytotoxicity of Ti-6Al-4V/ZrO2 composite fabricated by directed energy deposition for implant biomaterial

Abstract Ti-6Al-4V (TC4) has been widely used in dentistry as an implant biomaterial but is faced with difficulties in forming parts by traditional processing methods. Directed energy deposition (DED), a promising additive manufacturing technology, is very suitable for developing TC4/ZrO2 composite with different proportions of nano-ceramic additions (0, 5 or 10 wt.%). As the content of alloying element Zr increased, the grains were refined, and the lattice distortion was more severe due to solid solution, both of which caused Vickers hardness of the composite to increase from 308 to 485. The electrochemical tests and corrosion morphology analysis indicated that the corrosion was intensified with the decrease of pH and the increase of F− ion concentration. The corrosion product detection showed that ZrO2 oxide might reduce the compactness of the TC4 passive film containing TiO2 and Al2O3, which resulted in a slight decrease in corrosion resistance but still satisfied the clinical requirements. Cytotoxicity and cytoskeleton staining results demonstrated that the composite was beneficial to biological safety and biocompatibility.