Additively manufactured porous titanium alloy scaffolds for orthopaedics: An effect of process parameters on porosity

Abstract

Titanium alloys have been widely used as metallic materials for additive manufacturing, especially selective laser melting in recent decades because of its great corrosion resistance, excellent mechanical properties and bio- compatibility. Solid titanium alloys have higher compressive strength and elastic modulus than natural human bones and to get similar results that of human bones, solid titanium alloys are replaced by porous titanium alloys to fulfil the orthopaedic demands in biomedical applications. In this study two different types of Ti scaffolds (Grid and Vinties, each of two, total number of four) were designed using 3D CAD software with 65% porosity and fabricated through SLM process. The process parameters, employed in the work like laser power, hatch distancing, scanning speed, and layer thickness are the most effective factors that affect the porosity of the SLM-fabricated samples. The results demonstrate that when the porosity percentage increases, the energy density, scanning speed, and hatch distancing rise, but the laser power drops. This study primarily focuses on to determine porosity of the fabricated scaf- folds by Archimedes principle and optimizing the process parameters. Finally, compressive test is carried out on the scaffolds in an INSTRON machine of maximum ± 25 kN load capacity. The result shows better capability to man-ufacture with minimum error in porosity percentage and good potential for orthopedic applications as metallic implants.