The Effects of Pore Size and Heat Treatment on Compression and Corrosion Properties of Ti-6al-4v Sheet-Based Gyroid Implants Fabricated by Laser Powder-Bed Fusion

Abstract

The mechanical performance and corrosion behavior are crucial factors for additively manufactured Ti-6Al-4V porous implants, which are influenced by implant design, fabrication method, and post-processing. In the present study, effects of geometrical parameters and heat treatment on the compression and corrosion properties of Ti-6Al-4V sheet-based gyroid implants fabricated by laser powder-bed fusion (LPBF) process are investigated. The results showed that an increase in the pore size (ranging from 600 to 1200 µm) did not alter the microstructure, while decreased the Young’s modulus and strength of the implants. The post-processing heat treatment resulted in the α'  ® α + β phase transformation which influenced mechanical properties. The mechanical properties of all scaffolds were found to be comparable to those of human bone. The heat-treated implants showed superior corrosion resistance than the as-built ones. Furthermore, the corrosion resistance of both the as-built and heat-treated implants improved with increasing the pore size. The LPBFed Ti-6Al-4V implants with gyroid-sheet structure can be a promising candidate for biomedical implants under both compressive and corrosive conditions.

Keywords: Ti-6Al-4V implant, Gyroid structure, Laser powder-bed fusion, Compression properties, Corrosion behavior