Metal Additive Manufacturing Conference - MAMC 2020

Additive manufacturing (AM), in contrast to conventional manufacturing technologies, can produce functionally customized metal components of complex shape and geometry directly from 3D computer model, joining materials layer upon layer. Representative additive manufacturing technique, Selective Laser Melting (SLM) based on the complete-melting energy density for titanium alloy was investigated in this study. Due to their good mechanical properties and biocompatibility, titanium and titanium alloys are most commonly used in biomedical engineering, e.g. production of custom medical implants and prostheses. Titanium-Aluminum-Niobium (Ti6Al7Nb), shorter Ti67 alloy is a part of new generation of Ti-alloys that have improved biotolerance properties. In fact, so far the most widely used Ti-alloy in biomedicine, Titanium-Aluminum-Vanadium (Ti6Al4V), contains vanadium ions, which current scientific studies show are harmful. In order to start using selectively laser-melted Ti67 alloy for biomedical purposes, the effects of energy density (ED) and further process parameters on density, porosity and microstructure of cuboid Ti67 samples were examined. Laser power, scanning speed, hatch distance and powder layer thickness as process parameters were set corresponding to the thermodynamically calculated ED. Additionally, some of the samples were printed in three different orientations in order to study the effect of the building orientation on the microstructure. The density of printed samples was measured using Archimedes principle. Light and scanning electron microscopic investigations were used for determination of microstructure, more specifically to see the effect of pore formation on the parts density. Study with wide range of process parameters lead to an optimized process for this Ti-alloy with high density up to 99,36% and a fine grained and porous-free microstructure. Keywords: additive manufacturing, biomedical engineering, selective laser melting, Ti6Al7Nb