Avaliação da sinterização de ligas de Ti-Nb para aplicação biomédica

Abstract

Titanium alloys have several applications, due her mechanical properties, like low density and high resistance specific. They stand out especially in biomedical application, for present biocompatibility. The alloy Ti-6Al-4V is the most used commercially, however recent studies have connected the aluminum to neurological diseases, like the Alzheimer, and the vanadium to release toxic component into the bloodstream. Therefore, studies in this area that propose an alternative alloy are of fundamental importance. In this context, niobium presents itself as a potential substitute, since it is a non-allergenic, non-toxic element and has biocompatibility. For this purpose, in this work, specimens of two alloy compositions (Ti-22Nb and Ti-40Nb) were manufactured by a hot compaction process that physically simulates the injection powder molding, combined with an alternative sintering route with molten salt protection. The specimens were evaluated for porosity, microstructure, Vickers microhardness and resistance to compression. The Ti-22Nb alloy exhibited mechanical properties superior to Ti-40Nb. The sintering temperature was sufficient to promote the sintering of titanium and the formation of β phase in both alloys, however, due to the lower amount of niobium, the densification of the specimens of the Ti-22Nb alloy was higher. The process of sintering with molten salt protection proved to be efficient, in order to avoid the oxidation of the samples. However, there was no formation of a homogeneous structure in the samples, which is related to the relatively large particle size of the niobium powder. The results obtained in this work suggest that the combination of injection molding of metal powders and sintering with molten salt protection is viable approach for the production of biomedical implants based on Ti-Nb .