Mechanical and tribological characterization of NiTi cellular structures made by selective laser melting, aiming orthopedic implants

Abstract

This study assesses the mechanical and tribological performance of Nickel-Titanium (NiTi) cellular structures, aiming their integration in orthopedic implants. For that purpose, Selective Laser Melting (SLM), a metal additive manufacturing technology was used to manufacture NiTi cellular structured specimens, with different open cell sizes and wall thicknesses. Results revealed that the selected fabrication parameters were adequate for achieving high-quality cellular structures with open cells for bone ingrowth in orthopedic implants. Elastic modulus lower than that of bulk NiTi were obtained, opening the possibility to combine an outer layer of this NiTi structure with an inner region having higher stiffness, in order to globally match the elastic properties of bone. The tribological characterization allowed concluding that even structures with higher controlled porosity, presented adequate wear resistance. These structures are a promising solution for orthopedic implants looking ahead to implants customization according to patient-specific designs and suitable properties.