Influence of the precipitates on the shape memory effect and superelasticity of the near–eutectoid Ti–Au–Fe alloy towards biomaterial applications

Abstract

Influences of the Fe addition in various concentrations on the near–eutectoid Ti–4Au alloys were systematically investigated in this study in consideration of the great number of requirements for the biomedical materials. The Ti–4Au–xFe (x = 1, 3, 4, 5, 6, and 7 at.%) alloys were synthesized by physical metallurgy and their microstructures, crystal structures, lattice parameters, phases, and mechanical properties were analyzed. In addition, the investigations for the shape memory effect (SME) and superelasticity (SE) were also conducted to examine their performances of functionality. The β–phase was stabilized at room temperature by the 3 at.% addition of Fe into the binary Ti–4Au alloy. The specimen with optimized mechanical properties by trading–off its strength and ductility was found in the Ti–4Au–4Fe alloy. SME was revealed clearly in the Ti–4Au–3Fe alloy and slightly in the Ti–4Au–4Fe alloy; while SE was observed in the Ti–4Au–4Fe alloy. It was observed that there was a growing trend of the Ti3Au precipitate amount with the raised concentration of Fe addition. The precipitates of the Ti3Au were fine–tuned by the Fe addition for tailoring the various mechanical properties of the ternary Ti–4Au–xFe alloys, and the balanced performance was achieved by the 4 at.% Fe addition.