| Ti-29Nb-13Ta-4.6Zr(TNTZ) alloy has been developed based on the d-electron alloying design as a beta-type biomedical titanium alloy. It is preferred metallic materials for hard tissue implant applications due to its high specific strength, low Young's modulus (closing to that of human bone tissue, approximately 60 GPa), excellent biocompatibility. However, as a titanium alloy, the corrosion wear characteristics of TNTZ are not excellent enough because of its low shear resistance. The rare-earth-oxide Y2O3 is added to TNTZ designed to improve the corrosion wear characteristics in human body. The effects of Y2O3 on the corrosion wear characteristics of TNTZ were investigated, and the effect mechanism by Y2O3 on the interaction between corrosion and wear was also discussed. The results of the study are expected to provide the new method for improving the corrosion wear properties of TNTZ alloy.Y2O3 was added to TNTZ with different masses, and Y content was 0.05%,0.10%, 0.20% respectively. The UMT-2 friction-wear tester was used to test the friction wear properties of Y2O3/TNTZ alloys in air, in distilled water and in simulated body fluid (SBF), respectively. The weight loss was measured using a precise electric balance. Both a Scanning Electron Microscope (SEM) and a Laser Scanning Confocal Microscope (LSCM) were used to examine the surface of Y2O3/TNTZ alloys after friction wear testing.The results show that the wear resistance of TNTZ alloy in air is improved with adding of Y2O3. It is found that the adhesive wear is the prodominant wear mechanism in the air. Wear resistance of TNTZ alloy added with Y2O3 can be improved through inhibiting the dislocation motion and restraining the crack propagation by dispersion strengthen of Y2O3 particles, while improving the hardness by Y2O3 particles. The weightloss and friction coefficient of Y2O3/TNTZ alloys in distilled water and in SBF decrease due to the lubrication and cooling effect of water. It is clear that the adhesive wear is the prodominant wear mechanism in distilled water and SBF.Corrosion wear resistance of TNTZ alloys in SBF can be highly improved with adding of Y2O3, comparied with those in air and distilled water. On one hand, the wear resistance of TNTZ alloy added with Y2O3 particles can be improved through inhibitting the dislocation motion and restraining the crack propagation by dispersion strengthen of Y2O3 particles. On the other hand, the dissolution of passive film can be inhibited by adding of Y2O3 particles, thus a stable and compact passive film is accelerated to build to inhibite the corrosion; meanwhile, Y2O3 particles can protect the matrix as a corrosion resistant phase. Based on discussion above, the acceleration of corrosion on wear is inhibited by adding of Y2O3, thus the corrosion-wear resistance is susscfully improved. |
PDF Full Text Request