Microstructure and Mechanical Properties of Biomedical Ti-27Nb-8Zr Alloy with Low Elastic Modulus

Microstructure evolutions of Ti-27Nb-8Zr (mass fraction, %) biomedical alloy subjected to different aging treatments after solution treatment were studied by optical microscopy, scanning electron microscopy and X-ray diffraction, and the influence of various microstructures on the elastic modulus and tensile strength was discussed. The results indicate that the Ti-27Nb-8Zr alloy after solution treatment consists of beta+alpha" phases and has relatively lower elastic modulus and tensile strength, while for the alloy after aging treatment, it contains beta, alpha and omega phases and exhibits significantly higher elastic modulus and tensile strength. With increasing of the aging temperature, the microstructure became coarser and the elastic modulus and tensile strength became lower. It is recommended that a Ti-27Nb-8Zr alloy with comparatively lower elastic modulus (85.5 GPa) and optimal comprehensive properties can be obtained by adopting following process: solution treatment at 800 degrees C for 1 h and then quenched, aged at 500 degrees C for 12 h then air-cooled.