Fabrication and Mechanical Properties of Porous Ti-24Nb-4Zr-8Sn Alloy Devel-oped for Biomedical Application

摘要

Metal-based porous materials are currently the preferred choice as bone/cartilage implants due to their idiographic porosity improving the biocompatibility of implants. Ti-24Nb-4Zr-8Sn (in weight percent and abbreviated as Ti2448) is a new beta-type titanium alloy developed for biomedical application. The alloy possesses low modulus, high strength, good corrosion resistance in the physiological environment and non-toxicity. This study focuses on the fabrication and mechanical properties of porous Ti2448 alloy aimed for use as load-bearing implants. A bulk porous biomedical Ti2448 alloy was prepared by powder-metallurgy technique including cold-roll forming and vacuum sintering. The effects of processing parameters, such as rolling reduction, size and volume percentage of space-holder on porosity, average pore size, compressive strength and Young's modulus of porous Ti2448 alloy were investigated. The results showed that porous Ti2448 alloys of 17.6%~46. 8% in porosity, 166~ 509 μm in average pore diameter,30~325 MPa in compressive strength and 2. 3~27. 2 GPa in dynamic modulus can be fabricated by controlling process parameters. Compared with porous CP Ti fabricated by the same method,porous Ti2448 alloy has much higher strength-to-modulus ratio and better mechanical compatibility, which may greatly reduce stiffness mismatch between implant and bone after implantation.