| Titanium and its alloys are more widely used in clinical because it’s similar bone elastic modulus, good biocompatibility and excellent corrosion resistance in biological environments. But clinical materials used are still a high modulus of elasticity, including the lack of toxic elements (Al,V).In recent years, in order to achieve titanium alloy implant materials of low elastic modulus quantization to bones, joints, teeth, adding elements of non-toxic (alloy added an element of human tissues and organs were completely inert) and has a high compressive strength and excellent wear properties.Researchers add non-catatonic metal element Nb, Ta, Zr, as an added element to the titanium base, design almost P-type Ti-29Nb-13Ta-4.6Zr alloy. At present only the vacuum consumable arc furnace or vacuum powder metallurgy method of preparation.just as the addition of Nb, Ta, Zr belong to the high melting point,While use the vacuum consumable arc furnace melting Ti-29Nb-13Ta-4.6Zr alloy will first need different alloy raw materials to suppress welded into the electrode, then through multiple remelting the ingot. in the preparation of the electrode process will oxidation of materials, in the smelt process will composition segregation, in homogeneity, and inclusions, holes and other casting defects.Vacuum powder metallurgy method of preparation of Ti-29Nb-13Ta-4.6Zr alloy can effectively improve the material oxidation, component segregation, uneven phenomenon. But using the traditional non-pressure powder metallurgy method to the preparation of Ti-29Nb-13Ta-4.6Zr alloy due to the high sintering temperature and holding time sintering, there are a lot of holes in the material, which will lead to material degradation.Spark plasma sintering method of preparation of Ti-29Nb-13Ta-4.6Zr alloy can better solve the traditional method of preparation of Ti-29Nb-13Ta-4.6Zr alloy appears just because spark plasma sintering method has a low sintering temperature, fast heating and cooling (100℃/min or more), the sintering time is short, high density, preparation of clean advantages, can effectively inhibit the materials grain growth during sintering, can not only obtain a strong bonding force between the particles, the composition and homogeneous, relatively dense and high alloy materials, and can be controlled through the organization makes the alloy microstructure refinement to improve the overall performance of materials.Based on the above discussion, in this study were prepared by spark plasma sintering of Ti-29Nb-13Ta-4.6Zr alloy. Systematic study of the influence of sintering temperature on the microstructure, mechanical properties and electrochemical performance. And to study the micro-heat treatment on alloy microstructure and mechanical properties of impact, the following conclusions:(1)spark plasma sintering preparation of TNTZ the alloy density tended to increase with increasing sintering temperature, relative density reached99.4%in the1150℃;(2)sintering state TNTZ alloy with sintering temperature, the unmelted particles gradually decreases and the size is getting smaller and smaller; after solution treatment, the alloy in the (3phase. After aging treatment, the precipitation at the grain boundaries of a phase at the grain boundaries gradually showed clusters.(3)the alloy of compressive strength with the sintering temperature increased, the compressive strength after solution treatment decreased slightly, with the growth of the aging time (aging temperature is450℃), the compressive strength first decreased and then increased, the material the plastic first and then drop.(4)TNTZ alloy solid solution at850℃,450℃aging172.8ks (48h) can get the best mechanical properties:compressive strength of800MPa, compress the lowest average value of the modulus of elasticity E≈49GPa.(5)discharge ion sintering TNTZ to alloy with good passivity and corrosion resistance, the corrosion potential increase with increasing temperature.(6)with the sintering temperature, TNTZ sample polarization resistance Rp as the sintering temperature decreased, the anodic dissolution of the passive film becomes easy, increase in the corrosion rate, which is due to the nucleation of the met stable promote the growth of holes, the alloy passivity is stronger, smaller impedance. |
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