Microstructure, wear resistance, and corrosion performance of Ti35Zr28Nb alloy fabricated by powder metallurgy for orthopedic applications

A ternary Ti35Zr28Nb alloy was fabricated by powder metallurgy (PM) from pre-alloyed powder. The microstructure, hardness, corrosion behavior, and wear response of the produced alloy were investigated systematically. The results show that nearly full dense Ti35Zr28Nb alloy (relative density is 98.1 +/- 1.2 %) can be fabricated by PM. The microstructure was dominated with uniform beta phase. The Ti35Zr28Nb alloy displayed spontaneous passivity in a naturally aerated simulated body fluid (SBF) solution at 37 +/- 0.5 degrees C. The Ti35Zr28Nb alloy exhibited the highest corrosion resistance as compared to as-cast Ti6Al4V and pure Ti because of the formation of a protective passive film containing TiO2, Nb2O5, and ZrO2, including the highest corrosion potential (-0.22 +/- 0.01 V), the lowest corrosion current density (57.45 +/- 1.88 nA), the lowest passive potential (0.05 +/- 0.01 V) and the widest passivation range (1.29 +/- 0.09 V). Under the same wear condition, the wear rate of the Ti35Zr28Nb alloy (0.0021 +/- 0.0002 mm(3)/m.N) was lower than that of the CP Ti (0.0029 +/- 0.0004 mm(3)/m.N) and close to that of the Ti6Al4V (0.0020 +/- 0.0003 mm(3)/m.N). The wear mechanism of the Ti35Zr28Nb alloy was mainly dominated by abrasive wear, accompanied by adhesive wear. The highest corrosion resistance together with the adequate wear resistance makes the PM-fabricated Ti35Zr28Nb alloy an attractive candidate for orthopedic implant materials. (C) 2019 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.