Laser surface powder alloying of titanium with niobium and molybdenum

Abstract

Surface modifications have been used in titanium implants in order to increase the implant-bone interaction, such as the formation of surface roughness or porosity, or increase biocompatibility, wear and corrosion resistance by depositing special coatings. However, such modifications usually decrease the fatigue resistance. On the other hand, the specific surface modifications used to increase the fatigue resistance does not meet the typical requirements for biomaterials, such as good interaction with bone tissue, wear and corrosion resistance. The main objective of this research project is to develop a titanium surface modification that can increase the fatigue strength without affecting other implant requests. To achieve this aim, titanium and Ti-6Al-4V alloy parts will be modified by laser surface powder alloying, producing chemical composition gradients that stabilizes the titanium phase at the surface. We hope that the lower elastic tension developed at the surface due the lower Young modulus can delay the fatigue crack initiation, increasing the fatigue resistance. Niobium and molybdenum powder will be used, providing ²-phase-stabilizer elements to the alloy. The coating will be characterized to determine their microstructure, phases present, hardness and elastic modulus. The results of this project can make a significant contribution to the use of titanium in prostheses and, more broadly, with structural purposes. (AU)