Structure, Phase Composition, and Mechanical Properties of Biocompatible Titanium Alloys of Different Types

Abstract

The structure and phase composition of biocompatible titanium alloys of composition (wt %) Ti–10Zr–1.2Nb–1.5Al, Ti–6Al–4V (ELI), Ti–15Mo, and Ti–36.1Nb–3.8Zr–2.4Ta–1.9Sn have been studied in a hot-deformed state using scanning electron microscopy and X-ray diffraction analysis. The analysis of mechanical tensile properties has been performed depending on the structure and the aluminum strength equivalent of the alloys. The elasticity moduli of the alloys have been determined using tensile tests, dynamic mechanical analysis, and microindentation; the comparability of values within the error of 3–7% has been established. The nonmonotonic character of the change of the elasticity modulus upon heating to 550°C is explained in terms of the occurrence of processes of stress relaxation and recovery in the Ti–10Zr–1.2Nb–1.5Al, and Ti–6Al–4V ELI alloys and based on the precipitation of the high-modulus ω phase in the Ti–15Mo alloy. For the Ti–36.1Nb–3.8Zr–2.4Ta–1.9Sn alloy, the realization of the elinvar effect has been demonstrated. A correlation of the rate of change in the elasticity modulus with the heating temperature and the ratio of α and β phases in the structure of the alloys has been established.