Preparation and mechanical performance analysis of porous Ti6Al4V scaffold fabricated by direct ink writing

In order to mitigate the stress-shielding effect resulting from the stiffness disparity between titanium alloy and bone, the use of additive manufacturing to create porous Ti6Al4V components shows promise for orthopedic implant applications. In this study, a novel hot-melt–quick-frozen polyvinyl alcohol hydrogel was developed for direct ink writing to create porous titanium structures using Ti6Al4V powders with an irregular morphology. The rheological and sintering properties of inks with varying solid phase contents were examined to assess their molding quality. Furthermore, the effect of porosity on the morphology, shrinkage, and mechanical properties of the scaffolds was thoroughly investigated. The results of the experiments show that inks loaded with 65 vol. % Ti6Al4V particles exhibit the highest printing performance. Furthermore, the analysis revealed a positive correlation between the total porosity of the scaffold and its mechanical performance. In particular, the strength of the scaffold with a porosity of 54.8% exceeded that of human bone, and it also exhibited matched stiffness. Upon analyzing the final microstructure and mechanical properties, it is evident that these scaffolds meet the necessary criteria for use as orthopedic implants.