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A low Young's modulus is required for titanium alloys used in orthopedic implants, such as hip prosthetic stems, in order to avoid stress shielding due to a large difference in Young's modulus between the prosthetic stem and the cortical bone. The low Young's modulus has been observed to occur in metastable b-Ti alloys by precipitation of a stress-induced a 00 martensite during cold deformation. Under this context, the Influence of thermo-mechanical processing on the microstructure and mechanical properties of the metastable b Tie29Nbe2Moe6Zr alloy was studied as well as the influence of the degree of deformation by cold rolling with subsequent annealing after homogenization heat treatment. The alloy presents a b microstructure after solution heat treatment at 1000 C for 24h, followed by water quenching, while posterior cold rolling induces the precipitation of a" martensite. Young's modulus decreases and hardness increases with the degree of deformation. The annealed samples showed higher hardness and Young's modulus than the cold rolled samples. A thickness reduction of 90% maximizes the hardness/Young's modulus ratio and optimizes the required mechanical properties for orthopedic implants. The results indicate that the alloy is a promising alternative for the widely used Tie6Ale4V.

Metastable β-Ti alloys have become one of the most attractive implant materials due to their high biocorrosion resistance, biocompatibility, and mechanical properties, including lower Young’s modulus values. Mechanical properties of these alloys are strongly dependent on the final microstructure, which is controlled by thermomechanical treatment processing, in particular the Young’s modulus and hardness. The aim of this work was to analyze the influence of phase precipitations in heat-treated Ti–12Mo–xNb (x = 0, 3, 8, 13, 17, and 20) alloys. The alloys were prepared via arc melting and treated at 950 °C/1 h, and then quenched in water. The microstructures were analyzed by optical microscopy, transmission electron microscopy, and X-ray diffraction. Mechanical properties were based on Vickers microhardness tests and Young’s modulus measurements. Microstructural characterization showed that α″ and ω stability is a function of Nb content for the Ti–12Mo base alloy. Nb addition resulted in the suppression of the α″ phase and decrease in the ω phase volume fraction. Although the ω phase decreased with higher Nb contents, ω particles with ellipsoidal morphology were still observed in the Ti–12Mo–20Nb alloy. The α″ phase suppression by Nb addition caused a marked increase in the Young’s modulus, which decreased back to lower values with higher Nb concentrations. On other hand, the decrease in the ω phase continuously reduced alloy hardness. The study of the effect of chemical composition in controlling the volume fraction of these phases is an important step for the development of β-Ti alloys with functional properties.

Metastable β titanium alloys are developed for biomedical applications due to their low Young’s moduli and functional properties. These alloys can be fitted to different parts of orthopedic implants through thermomechanical processing and chemical composition control. This study aimed to produce, process, and characterize a new metastable β titanium Ti-23.6Nb-5.1Mo-6.7Zr alloy on a semi-industrial scale for orthopedic implant manufacturing, and to discuss the influence of the cold rolling and transformed phases during aging in the microstructure and mechanical properties. This alloy was produced in a vacuum arc remelting furnace (VAR) and thermomechanically processed under different conditions. The samples were characterized by X-ray diffractometry, optical, and scanning electron microscopy, and Young’s modulus (YM) and Vickers Hardness (HV) tests. Among other processing conditions, the sample that was 50% cold rolled after solution treatment, which resulted in a microstructure with β and α″ phases, had the lowest YM (~57 GPa), and the sample aged at 300 °C for 2 h had the highest HV/YM ratio (5.42). The new alloy produced in this work, processed by different routes, showed better mechanical properties than most recently developed metastable Ti-β Alloys.

The development of β-metastable titanium alloys that combine low Young's modulus, good mechanical properties, corrosion resistance and biocompatibility has attracted industry interest. This type of alloy is an alternative to commercial alloys such as Ti-6Al-4V, avoiding the cytotoxic effect that occurs with Al and V in the human body in the manufactured orthopedic prostheses. In this scenario, the present work aims to characterize the effect of Nb concentration in the properties of Ti alloys based on the Ti-12Mo-xNb stoichiometry (x = 0, 3, 8, 13, 17 and 20). All alloys were produced by arc melting with non-consumable tungsten electrode in an argon atmosphere and the ingots were characterized by x-ray diffraction (XRD), optical microscopy (OM), Vickers microhardness and Young's modulus was measured by impulse excitation and density was measured using the Archimedes' principle. The Ti-12Mo alloy and the Ti-12Mo-20Nb alloy showed the lowest Young's modulus. The best hardness/ modulus was found for the Ti-12Mo-3Nb alloy. All the alloys studied in this work showed hardness/ modulus ratio above the traditional Ti-6Al-4V alloy (2.85), presented great potential for the biomedical application.