Improving mechanical properties and antibacterial response of α/β ternary Ti–Ta alloy foams for biomedical uses

Abstract

This study investigates the potential of Ti–Ta–Sn alloys for biomedical applications due to their excellent mechanical properties and biocompatibility, with a particular focus on their use in trabecular bone replacement. This work aims to analyze the influence that of Sn has on the mechanical properties and antibacterial response of α−β ternary Ti–13Ta–xSn (x:3, 6, 9, and 12 at.%) alloy foams. The Ti-based alloys were designed considering three aspects; (i) final microstructure, (ii) alloying element types, and (iii) thermodynamics while using MAAT and ThermoCalc software. The alloys were obtained by mechanical alloying, with used milling times being 30 h for Ti–13Ta–3Sn, 10 h for Ti–13Ta–6Sn, 10 h for Ti–13Ta–9Sn, and 15 h for Ti–13Ta–12Sn. The foams were obtained using NaCl as the space holder (50 v/v% porosity) and consolidated by a hot pressing method at 780 °C for 30 min, applying a load of 40 MPa. Both the Staphylococcus aureus ATCC 6538 strain and Escherichia coli ATCC 8739 strain were used to evaluate the antibacterial responses of Ti-based alloy foams. The Ti-based alloy foams were composed mostly by a mix of α and β-phases. The metallic foams exhibited relative homogeneous pore distribution with a size between 100 and 450 μm and having an average porosity slightly higher than 50%. The samples showed elastic modulus values between 1 and 2 GPa, compressive yield strengths over 150 MPa, and microhardness over 450 HV. All Ti-based alloy foams showed no antibacterial activity nor bacterial adhesion, indicating that there is bacterial adhesion inhibition.

Keywords

• Hardness
• X-ray analysis
• Titanium alloys
• Powder methods