Fabrication And Property Research Of Ti-Zr-Si Amorphous Alloys System

Based on the phase diagrams of Ti alloys and 3d electron theory, this dissertation deals with design and preparation of Ti-Zr-Si amorphous alloys system such as T17, TF14, TFM23 and TFMN31 without toxic elements by especially taking the applications of Ti alloys as biomaterials into account. The phase compositions were determined by X-ray diffraction patterns. The surface topography was observed using TEM. The glass forming ability (GFA) of Ti-Zr-Si amorphous alloys was evaluated by Inoue's experimental rules and characteristic temperatures, respectively. The bioactivity of Ti-Zr-Si amorphous alloys was tested in simulated body fluid (SBF). The corrosion resisting properties of Ti-Zr-Si amorphous alloys were explained by polarization curves in NaCl and PBS solutions. And Young's modulus and fracture strength were investigated by stress-strain curves of Ti-Zr-Si amorphous alloys.The X-ray diffraction patterns results showed that the T17, TF14, TFM23 and TFMN31 own amorphous structure.The GFA of the alloys changed more continuously in the order of TFM23 > T17 > TF14 > TFMN31. Firstly, the values of mixing enthalpy of the four alloys were all less than zero and the order from the greatest negative value to the smallest was indicated as follows: TFM23 > T17 > TF14 > TFMN31. Secondly, the region of supercooled liquid (â–³Tx), the reduced temperature (Trg) and theγcriterion varied in order of TFM23 > T17 > TF14 > TFMN31, which was consistent with the results of Inoue's experiential rules.The bioactivity of the four amorphous alloys was tested in SBF. It was found that a compact and netlike and porous layer had been deposited on the surface of alloys after 15 days, which were helpful for the bone cell to conglutinate and proliferate. The element analysis result of the deposition tested by EDS showed that the depositions were composed of Ca, P, O and C etc., and n (C a)n(P) ratio for the deposition is about 1.6 which approached to that of Human bone of 1.66. In addition, the results of IR absorption spectra of deposition showed that the deposition contain OH- and PO₄^3– etc., which confirmed that the deposition consisted of HA.The polarization curves of T17, TF14, TFM23 and TFMN31 in NaCl and PBS solutions showed that T17, TF14, TFM23 and TFMN31 owned excellent corrosion resisting property, compared with amorphous Ti60Zr10Ta15Si15 with excellent corrosion resisting property. In 3% mass NaCl solution at 298K, pitting corrosion generated in TFMN31, whose potential of pitting corrosion was 1750 mV. And, in PBS solution at 310K, pitting corrosion generate in TF14, whose potential of pitting corrosion was -699.17 mV.The stress-strain curves indicated that the values of Young's modulus of the four amorphous alloys were lower than that of crystals with identical component. Elastic-plastic deformations occurred in the four alloys when the test samples bore stress. The fracture strength and elongation ratio of the TFMN31 were the highest in the four amorphous alloys. In addition, a lot of slipping band could be seen on amorphous surface. At the same time, great deals of dimples appeared on the surface of the fracture which was typical fractography of ductile rupture.