Composition Dependence of the beta Phase Stability and Mechanical Properties of Ti-Nb Thin Films

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.