ABSTRACT
Shape memory alloys (SMAs) are commonly used for various applications, e.g., in the aerospace and automotive industries, robotics, and biomedical sciences. Although Ti-Ni SMAs are commercially available, the low biocompatibility of Ni has stimulated research into the development of Ti-Nb based SMAs as potential replacements of Ti-Ni alloys in biomedical applications. Ti-Nb alloys have attracted attention because of their low stiffness and superelasticity. Superelastic thin films can be used in medical applications, including the fabrication of stents for neurovascular blood vessels, which relies on a thin film and on the use of a Ti-Nb alloy coating for less biocompatible alloys. In this study, Ti-Nb thin films were prepared using magnetron sputtering. A Nb content in the range 12.2-35.9 at.% was used in the films, which was determined using energy-dispersive X-ray spectroscopy. X-ray diffraction measurement was used to analyze the crystal structure of the thin films, and their mechanical properties were investigated using nanoindentation.
ABSTRACT
Ternary Ti-Nb-Zr alloys were prepared by a magnetron sputtering method with porous structures observed in some of them. In bulk, in order to control the porous structure, a space holder (NH4HCO3) is used in the sintering method. However, in the present work, we show that the porous structure is also dependent on alloy composition. The results from Young's modulus tests confirm that these alloys obey d-electrons alloy theory. However, the Young's modulus of ternary thin films (≈80â»95 GPa) is lower than that for binary alloys (≈108â»123 GPa). The depth recovery ratio of ternary Ti-Nb-Zr thin films is also higher than that for binary ß-Ti-(25.9â»34.2)Nb thin film alloys.
