Previous studies of new developed titanium alloys for biomedical applications

Abstract

The inereasing demand for metallie biomaterials in various medical fields and the problems often eneountered with eurrent conventional alloys have led to the determination of the influenee of four various silieon coneentrations on the mierostrueture, corrosion behavior, modulus of elastieity and hardness ofthe new TiMoZrSix (x = O, 0.5, 0.75, 1) alloy by means of metallographic, eleetrochemical, three-point bending and microhardness tests. The fabrication of these alloys was performed utilizing a voltaie are remelting (V AR) fumaee, in which a eonsumable electrode was melted in a vacuum ata eontrolled rate with heat generated by the electric are produced between the eleetrode and the ingot. Prior to the application of the research methodologies, the samples were embedded in epoxy resin cylinders for subsequent cutting and then, grinding and polishing with progressive grain silicon carbide abrasive papers and 0.1 micrometers alumina suspension. Finally, the samples were cleaned eompletely by immersing them in an ultrasonie maehine for 5 minutes [1,2]. After applying the different techniques, metallographic examination revealed that the four samples exhibited biphasic and dendritic structures, with the addition of silicon reducing the size of dendrites and increasing the interdendritic zone. According to electrochemieal studies performed in body simulation fluid, samples with higher silieon coneentrations corrode faster, while samples with lower silicon coneentrations show higher eorrosion resistanee. Electrochemical Impedance Spectroscopy measurements were performed at various potentials, and the obtained speetra revealed a two-time eonstant system, owing to the presenee of a double-layer passive film on the samples. Thus, it was demonstrated that the more positive the value of the applied potential, the higher the corrosion resistanee, presenting comparable impedance values. Moreover, the microhardness test suggested that the samples' surfaces had both soft and hard phases while the three-point bending test for the samples found that the values of modulus of elasticity were near to those of cortical human bone and lower than those of commercial alloys. Based on the results achieved, th is samples showed good and similar chemical, mechanical and biological characteristics, with the Til 5MoZrSi0.5 sample showing slightly superior mechanieal properties.