Product Code: ICAL09_M503

Laser-Assisted Development of Ti Alloys: The Search for New Biomedical Alloys
Authors:
Amelia Almeida, Instituto Superior Tecnico; Lisbon Portugal
Dheeraj Gupta, Instituto Superior Tecnico; Lisboa Portugal
Rui Vilar, Instituto Superior Tecnico; Lisboa Portugal
Presented at ICALEO 2009

Ti-alloys used in prosthetic applications are mostly alloys initially developed for aeronautical applications, so their behavior was not optimized for medical use. A need remains to design new alloys for biomedical applications, where requirements such as biocompatibility, in-body durability, specific manufacturing ability, and cost effectiveness are considered. Materials for this application must present excellent biocompatibility, ductility, toughness and wear and corrosion resistance, a large laser processing window and low sensitivity to changes in the processing parameters. Laser deposition has been investigated in order to access its applicability to laser based manufactured implants. In this study, variable powder feed rate laser cladding has been used as a method for the combinatorial investigation of new alloy systems that offers a unique possibility for the rapid and exhaustive preparation of a whole range of alloys with compositions variable along a single clad track. This method was used as to produce composition gradient Ti-Mo alloys. Mo has been used since it is among the few elements biocompatible, non-toxic beta stabilizers of Ti. Alloy tracks with compositions in the range 0-20 wt.% Mo were produced and characterized in detail as a function of composition using micro-scale testing procedures for screening of compositions with promising properties. Microstructural analysis showed that alloys with Mo content above 8% are fully formed of beta phase with a cellular morphology. Ultramicroindentation tests carried out to determine the alloys hardness and Youngs modulus showed that Ti-13%Mo alloys presented the lowest hardness and Youngs modulus (65 GPa) closer to that of bone than common Ti alloys, thus showing great potential for implant applications.