Microstructure and Mechanical Properties Change with Cold Deformation of the Biomedical Ti-17Nb-6Ta-3Zr Alloy

Abstract

This study is to investigate the phase stability, cold deformation, elastic strain recovery and mechanical properties of a new Ti-17Nb-6Ta-3Zr, at. %, alloy for biomedical applications. The alloy was produced by arc melting. A heavy cold-working up to 90 % was applied to the alloy to investigate the stability of the predominant β-bcc structure. Characterization of the deformed structures was performed by X-ray diffraction (XRD), hardness measurements and optical microscopy. Quasi-static compression testing was conducted to determine the yield stress for stress induced martensitic (SIM) transformation and the Young modulus. XRD analysis of the cold-worked structures revealed that α-martensite was induced after less than 5 % deformation. An outstanding combination of strength-elasticity properties with the yield strength of 600 MPa and a Young modulus of 37 GPa was achieved during the compression tests.

Microstructure and Mechanical Properties Change with Cold Rolling of New Ti-13Nb-1.5Ta-3Mo Alloy

“…A single β-phase structure with an average grain size of 325 μm was obtained after homogenization treatment. Moreover, the absence of α″ martensite phase implies that the content of the alloying elements (Nb, Ta and Mo) are high enough to retain after quenching fully β-phase at room temperature and bring martensite start temperature to below room temperature [12]. This micrograph satisfied the prediction of obtaining a single β-phase structure after homogenization treatment and water quenching when the Moeq value > 10 [13].…”

“…6 (B). The strengthening of metallic materials during cold work is usually ascribed to an increase in dislocation density as well as dislocation entanglement [12]. Fig.…”

“…The specimen exhibited three separate stages of curve, namely; (I) linear elasticity stage (II) plastic yielding stage and (III) parabolic stage which corresponded to the elastic-plastic foams' compressive stress-strain curve defined by Gibson-Ashby model [15]. The first stage is characterized by the elastic behavior of the alloy in relation to the elastic response of the parent phase [12]. The linear elastic stage happens when the unit cell bends and plastic yielding stage occurs when the compressive force begins to push the material causing the unit cell to collapse [15].…”

Superelasticity Evaluation of the Biocompatible Ti-17Nb-6Ta Alloy

“…Also the mechanical properties were investigated in the previous studies which proved good workability and ductility, besides achieving controllable strength [23, 26]. Also, a new study concerned to investigate the effect of adding the zirconium element for the TNT alloy on both microstructure and mechanical properties [27]. The potential of the TNT alloy to work as drug-eluting stents is also studied recently and showed very promising results [28].…”