Surface and morphological modification of selectively laser melted titanium lattices using a chemical post treatment

Titanium lattices produced using selective laser melting have received great interest as key elements in the development of bone substitute implants. However, as the inherent surface defects formed during the selective laser melting process are known to have a negative impact on mechanical and biological performances of the implants, it is crucial to modify the lattices at the surface level. In the following work, we investigate the use of a chemical post-treatment for the surface modification of Ti-6Al-4V lattice structures. Triply periodic minimal surfaces, a promising set of unit-cells for hard tissue engineering, have been used for the design of the specimens. Incremental polishing was conducted and the evolution of both surface and morphological properties have been reported with an increase in polishing time. The method has been successful in removing partially melted powder adhering to the surfaces within the interconnected lattice networks and reducing the stair stepping effect brought about by the manufacturing process. Morphological characteristics were found to be consistent throughout the samples, which indicates an adequate penetration of the etchant. It was found that the potential reduction in structural strength may be mitigated by oversizing the struts in the design phase of the lattices.