On the influence of sintering protocols and layer thickness on the physical and mechanical properties of additive manufactured titanium porous bio-structures

This article aims at a thorough study about the effects of sintering protocols and layer thickness on mechanical and physical properties of additive manufactured porous structures used in orthopedic applications. Stress shielding effects induced on the bone interfacial surfaces due to the fixation of the metallic implant must be minimized to prevent implant loosening resulting in inflammation and pain. To this end, controlling the mechanical and physical properties of the implant is crucial to address the abovementioned issue. This control can be enhanced by understanding the role of additive manufacturing parameters in anisotropic properties of titanium structures. In addition to the experimental tasks, a model was developed according to the microstructural arrangement of particles to predict the porosity of the produced structures. The results showed a good agreement between the developed model and the experimental results. Furthermore, with the variation of process parameters, titanium parts with a wide range of porosity (17-44%), Young's modulus (0.77-11.46 GPa), yield strength (27-383 MPa), and shrinkage (∼2-11%) were produced. Finally, the achieved porosity, young's modulus property and yield strength were comparable with the cortical bone properties.