Combinatorial laser-assisted development of novel Ti-Ta alloys for biomedical applications

Ti and its alloys are commonly used for biomedical implants. These alloys, developed for aeronautical applications, are not optimized for medical use. Major limitations of current alloys are the presence of elements that are toxic or associated to neurological disorders, and excessive stiffness, that leads to stress shielding and may result in bone resorption and implant failure. A need remains to design new alloys for biomedical applications that fulfill requirements such as biocompatibility, wear and corrosion resistance, and adequate stiffness, strength, toughness and fatigue resistance. Alloying Ti with β-phase stabilizers allows obtaining alloys with biomechanical behavior closer to that of bone than current ones. However, new materials development using conventional alloying techniques can be time-and resources-consuming, since it requires the production, characterization and testing of a significant number of discrete composition samples. In this study, the combinatorial method based on variable composition laser deposition is used to produce new Ti-based alloys with composition varying continuously along a single clad track. The alloys are then characterized and tested using microscale techniques, allowing a rapid screening of their structure and properties over a wide range of compositions. A summary of the results obtained for the Ti-Ta alloy system will be presented and discussed in terms of alloy constitution, microstructure and resulting properties, demonstrating the potential application of the laser-assisted combinatorial method to discover Ti alloys with most promising properties for biomedical load-bearing applications.