Enhancement in mechanical properties of a β-titanium alloy by high-pressure torsion

Abstract

Titanium alloys, mainly Ti–6Al–4V, are commonly used in biomedical applications as orthopedic implants. Due to the potential toxic influence of V and Al cations on health, a new alloy composition, Ti–24Nb–4Zr–8Sn, was introduced. However, Ti–24Nb–4Zr–8Sn has a much lower tensile strength by comparison with the Ti–6Al–4V alloy. The aim of this research was to determine whether high-pressure torsion (HPT) can be an efficient method for obtaining the desired properties in the case of the Ti–24Nb–4Zr–8Sn β-titanium alloy. This paper presents an analysis of the microstructural and mechanical properties of the Ti–24Nb–4Zr–8Sn alloy processed by HPT with various processing parameters. The obtained microstructures were examined using transmission electron microscopy (TEM). Mechanical properties, such as hardness and tensile strength, were also measured. The study demonstrates that HPT of the Ti–24Nb–4Zr–8Sn alloy leads to a significant reduction of grain size and this grain refinement gives a major improvement in tensile strength and hardness.

Keywords

• β-Titanium alloys
• High-pressure torsion
• Grain size refinement
• Mechanical properties