Development of Ti-Nb and Ti-Nb-Fe Beta Alloys from TiH_2 Powders

摘要

Ti-Nb β alloys are a promising alternative as an implant material due to their good properties and low Young's modulus, compared to other Ti-alloys currently employed as biomaterials. In this study, three materials of the Ti-Nb and Ti-Nb-Fe systems were produced by powder metallurgy techniques starting from TiH_2 (TH) powder. Several sintering cycles were employed to evaluate the H_2 elimination and the effect of sintering temperature on densification and fraction of β-Ti phase. Also, the influence of alloying element size using two kinds of Fe powder was evaluated. The highest loss of H_2 was achieved decreasing heating rate at the temperature range of hydride decomposition. SEM images and XRD results show mainly a β-Ti phase for TH40Nb and TH5Fe25Nb samples. The TH12Nb sample shows (a+β) microstructure. Fe addition with smaller particle size seems to improve the diffusion of Nb into Ti which promotes a higher β-phase fraction and sample homogeneity.