Study On The Fabriction, Structures And Properties Of The Amorphous Biomedical Ti-Zr-Fe-Si Alloy System

Base on the research status of amorphous Ti-alloys, this dissertation deals with the design and fabriction of the Ti-Zr-Fe-Si amorphous biomedical alloy system such as Ti12.5Zr10Si5Fe4Mo3Sn and Ti12Zr10Si5Fe2Sn (hereinafter short for TMS and TS) without toxic elements that have good biocompatibility and mechanical properties. The microstructure and phase structure in different states were observed and analyzed by XRD, SEM, TEM and metalloscope. The biocompatibility and corrosion resistance of amorphous alloys were systematically studied and evaluated by soaking them into simulate body fluid, blood compatibility test, immersion in vitro and electrochemical experiment. Using tensile test at room temperature, the alloys'mechanical properties were investigated. The results were as follows:1. Homogenizing annealing has the remarkable effect. The analysis results of XRD, TEM, SEM and DSC indicated that the TMS and TS prepared by rapid solidification method own amorphous structure, both of them have a good glass forming ability and their surface present disordered glass state.2. The results of soaking the alloy into simulate body fluid, dynamic clotting and hemolysis test showed that the TMS and TS have good biological activity and blood compatibility. The surface deposition layer was bioactive HA which was compact porous networks in shape, and its atom percentage of Ca and P was about 1.7. This value was very close to 1.67 of human bone's Ca/P value. 3. The results of immersion corrosion experiment in vitro showed that the TMS and TS exhibited satisfactory corrosion resistance in acid and neutral SBF solution, but it was relatively worse in alkaline electrolyte. Furthermore the results of electrochemical test indicated that the corrosion tendency of this two kinds of amorphous alloys were all very small in SBF solution and 0.9% normal saline. Based on their corresponding polarization curves got that the corrosion resistance of TMS and TS were very excellent in two kinds of corrosion medium.4. The stress-strain curves and SEM fracture morphology showed that the values of Young's modulus of TMS and TS were very lower than their corresponding crystalline alloys. And the more break elongation was proved that the alloys had a high ductility. Both of their fracture morphologys exhibited vein type, moreover the TS also appeared a lot of parallel distributed slip bands.