The Effect of Oxygen Addition on Microstructure and Mechanical Properties of Various Beta-Titanium Alloys

Simultaneously achieving high strength and low Young's modulus is essential for implant materials due to the "stress-shielding effect". In this work, the mechanical properties and microstructure of various beta-titanium alloys based on the Ti-Nb system with additions of Zr, Ta and Sn have been studied. Those alloys were prepared via the arc melting process. Thermo-mechanical processing (i.e., hot forging, solution treatment and cold swaging) has been performed. The alloys exhibited low Young's modulus around 50 GPa (43 GPa was the lowest measured value) and tensile strength around 800 MPa. The tensile strength was increased via aging treatment (450 degrees C/8 h) to 985 MPa while the modulus increased to 75 GPa. On the other hand the addition of 0.4 wt.% of oxygen seems to be more beneficial as the tensile strength reached values as high as 1225 MPa and simultaneously maintained low Young's modulus (similar to 62 GPa) and sufficient elongation (similar to 8%).