Production of a Novel Biomedical β-Type Titanium Alloy Ti-23.6Nb-5.1Mo-6.7Zr with Low Young’s Modulus

Abstract

Metastable β titanium alloys are developed for biomedical applications due to their low Young’s moduli and functional properties. These alloys can be fitted to different parts of orthopedic implants through thermomechanical processing and chemical composition control. This study aimed to produce, process, and characterize a new metastable β titanium Ti-23.6Nb-5.1Mo-6.7Zr alloy on a semi-industrial scale for orthopedic implant manufacturing, and to discuss the influence of the cold rolling and transformed phases during aging in the microstructure and mechanical properties. This alloy was produced in a vacuum arc remelting furnace (VAR) and thermomechanically processed under different conditions. The samples were characterized by X-ray diffractometry, optical, and scanning electron microscopy, and Young’s modulus (YM) and Vickers Hardness (HV) tests. Among other processing conditions, the sample that was 50% cold rolled after solution treatment, which resulted in a microstructure with β and α″ phases, had the lowest YM (~57 GPa), and the sample aged at 300 °C for 2 h had the highest HV/YM ratio (5.42). The new alloy produced in this work, processed by different routes, showed better mechanical properties than most recently developed metastable Ti-β Alloys.

Keywords

• orthopedic implants
• microstructure
• mechanical properties
• titanium alloys