Wear Behavior of Ti-xNb Biomedical Alloys by Ball Cratering

Abstract

Ti alloys have been developing through the years, aiming the biomedical application since it has suitable properties. Among Ti alloys, the Ti-Nb systems are a pronounced group to biomedical applications due to its low elastic modulus, good corrosion resistance, and mechanical properties. Although this system is quite well-known regarding its phases, structure and properties, there is not plenty of information about wear available in the literature. To investigate the wear resistance, the samples were submitted to x-ray diffraction (XRD) and scanning electron microscopy (SEM) to analyze the phases formed. Hardness and elastic modulus were measured by microhardness Vickers and dynamic Young modulus by excitation impulse. Additionally, wear volume, wear resistance, and H/E ratio were calculated to understand the wear material's performance. This study aims to investigate the wear resistance of Ti-xNb (x = 15, 25 and 40wt.%), one of each type of Ti alloys and phases formed: Ti-15Nb (α´), Ti-25Nb (α") and Ti-40Nb (β) and the influence of cooling rate after solution heat treatment on wear properties through ball cratering. It was possible to find that the harder the alloy, the higher the wear resistance. Thus, in the case of Ti-xNb (x = 15, 25 and 40wt.%), alloys the hardness plays a significant role in wear resistance. Besides that, the samples that have presented the α´ or α"phase have the lowest wear resistance. Therefore, not only the hardness influences the wear resistance but also the combination of phases formed.