Design and Development of Microporous Ti-35Nb-5Ta-7Zr Alloy and its Characterization

Abstract

Ti-35Nb-5Ta-7Zr titanium alloy is a Beta phase titanium alloy with good mechanical, excellent corrosion resistance, and better biocompatible properties. This study is focused on introducing porosity in the Ti-35Nb-5Ta-7Zr alloy with the intent to produce porous alloy with a suitable combination of low elastic modulus and yield strength. Porous Ti-35Nb-5Ta-7Zr alloy was fabricated in argon arc melting and yttrium was added in different proportions, followed by a chemical dealloying process. The developed porous alloys were thoroughly investigated after synthesis, including microstructural, corrosion and mechanical characterization. A microstructure based on a matrix mainly composed of BCC beta phase and interdendritic areas consisting of yttrium phase was formed by adding yttrium in Ti-35Nb-5Ta-7Zr alloy. With increasing amounts of yttrium in Ti-35Nb-5Ta-7Zr alloy, the amount of interdendritic regions increased. An X-ray diffractometry (XRD) examination confirmed that yttrium was removed through dealloying process. SEM investigation of the generated porous alloys revealed the formation of interconnected porosity. The developed porous alloys were evaluated through mechanical and corrosion testing. The mechanical evaluation of the manufactured alloys exhibited a broad spectrum of mechanical properties. Developed porous alloys showed elastic modulus and yield strength in the range 29.5 Gpa to 13.7 Gpa, and 293.98 MPa to 215.12 MPa, respectively. The mechanical properties achieved in this study were in the within acceptable limits of human bone and are for biomedical applications. Corrosion resistance of porous alloys showed a decreasing trend with an increase in porosity.