The microstructure and some properties of the novel biomedical ZrTiFe alloy subjected to high-pressure torsion deformation

Zr- and Ti-based alloys, due to their excellent mechanical, physical, and biological properties, are increasingly used as biomaterials. Although these alloys have been used in medical applications for over 60 years, several issues remain associated with their use in this field. For example, high-strength α or α + β titanium alloys are characterized by a too-high Young’s modulus, while β alloys have a low Young’s modulus but are characterized by low strength and fatigue properties. Therefore, obtaining biomedical alloys with high strength, good plasticity, and low Young’s modulus is a current challenge. The work was based on the assumption that phase transformations induced by severe plastic deformation followed by low-temperature annealing can optimize the mechanical properties of new biomedical nanocrystalline Zr–Ti–Fe alloys. For this purpose, the influence of high-pressure torsion (HPT) on the microstructure, phase transformations, microhardness, and Young’s modulus of the Zr–33Ti–1Fe (at%) alloy, pre-annealed at temperatures of 600, 800, and 930 °C, was first investigated. It was found that HPT causes partial phase transformations ( α → ω HPT and β → ω HPT ), significant microstructural refinement, and an increase of hardness to 5.1 GPa in the sample pre-annealed at 600 °C, as well as a slight microstructural refinement and a slight decrease in hardness and Young’s modulus in the samples previously annealed at 800 and 930 °C. The positive effect of HPT on the mechanical properties was observed using the three-point bending method: the strength and plasticity of the deformed alloy are twice those of the initial state, despite the presence of a predominantly brittle ω HPT phase.