Decomposition of martensite α″ during aging treatments and resulting mechanical properties of Ti-Ta alloys

Effects of Ta content and aging temperature on the decomposition of martensite α″ in the Ti-Ta alloys with Ta contents from 30 mass% to 50 mass% and the resulting mechanical properties, including the dynamic Young's modulus, were investigated for biomedical applications. The microstructures were examined using a scanning electron microscopy (SEM), a transmission electron microscopy (TEM) and an X-ray diffraction (XRD) analysis. The decomposition of martensite α″ phase in the Ti-Ta alloys depends on both Ta content and aging temperature. Various microstructures such as α, (β + ω) and (α + β) phases precipitate in the Ti-Ta alloys after the aging treatments are performed between 723 K and 873 K for 259.2 ks. The dynamic Young's modulus and mechanical properties of the Ti-Ta alloys are found to be sensitive to the microstructures caused by Ta content and aging temperature. The Ti-30% Ta alloy with α phase values much lower modulus and higher strength-to-modulus ratio than the currently used implant biomaterials, and thus has a great potential to become a new candidate alloy for biomedical applications.