Ti-Nb based alloys by direct ink writing

Additive Manufacturing is an innovative manufacturing technology, it is part of what is generally considered the fourth industrial revolution: Industry 4.0, allowing the production of very complex components with high performance and custom-made geometries. The development of this technology has already reached promising results that allows its use in various industrial and biomedical sectors, and it is expected that in the future its evolution will continue to have a greater diffusion. This technology has proven particularly promising in the field of titanium, a material known for its superior properties of strength, lightweight, and corrosion resistance, etc. This report aims to describe the functioning of Additive Manufacturing (AM) and to optimize the 3D printing process for different titanium alloy powder-based inks, including TNZ (Ti-22Nb-(2-6)Zr), TNT (Ti-22Nb-(6-8)Ta), and TNZT (Ti-35Nb-2Ta-3Zr). The optimization is achieved through an extrusion-based technology known as direct ink writing (DIW) or robocasting, specifically for the creation of scaffold structures with potential biomedical applications. The report examines the AM technique used for processing titanium via extrusion-based AM, evaluates its implications, and investigates its diffusion and impact in the biomedical sector. This process enables the development and testing of complex titanium alloy inks and components, which were previously unachievable. Subsequently, practical applications of AM in the titanium sector are examined, particularly titanium alloys TiNb with Zirconium, Tantalium and a combination of both. Their composition will be analysed in the field of biocompatible shape memory alloys, their chemical and physical characteristic. The 3D printing process will be optimized by identifying, through physical and chemical characterizations of the inks, the most suitable and optimized ink that is most representative for this objective. Starting from the study of the material, geometries, and the process, results have been obtained in terms of physical and mechanical characteristics required for the applications of the printed components. Finally, the challenges and future opportunities in the use of AM for these titanium alloys are explored after analysing the samples with chemical and physical characterization tests. These include the need to overcome technological limitations such as porosity and surface solidity, strength, as well as process optimization to ensure the quality and repeatability of the parts, but also, the search for materials with the most similar shape memory properties. Keywords: Additive Manufacturing, Direct Ink Writing, Robocasting, scaffolds, metal powders, titanium, titanium scaffold.