Development of a porous Ti-35Nb-5In alloy with low elastic modulus for biomedical implants.

Abstract

A new porous Ti-35Nb-5In alloy was designed to join the advantages of low elastic modulus and non-toxicity, which are critical factors for biomedical implants. The Ti-35Nb-5In alloy was produced by powder metallurgy, and its feasibility as implant material was evaluated through mechanical properties, ion release, and electrochemical assessments. The microstructure of the Ti-35Nb-5In alloy consisted of acicular α-phase and fine α''-phase within a micrometric β-phase matrix. A low elastic modulus of 63 GPa, as well as hardness and flexural strengths higher than the reported for the human bone, ensured the mechanical adequacy of the alloy. The Ti, Nb, and In releases were below toxic levels for the human body. The electrochemical performance showed the formation of a surface passive layer formation that encouraged a low corrosion rate. The corrosion performance was mainly influenced by chemical heterogeneities (preferred dissolution of Nb segregates) and porosity. Based on the above, the porous Ti-35Nb-5In alloy was demonstrated as a promising candidate for biomedical implant applications.