| Object:Titanium was widely used in medical field for its good mechanical, corrosion-resistance and biological properties. With the development of the casting technology, titanium, as dental restoration material, also showed its fine application prospect in the dental restoration field. At present, titanium and Ti-6A1-4V are most used in dental restoration field. Considering the low tensile strength, the bad wear resistance, and the difficulties in processing technology (casting, welding, polishing, etc.) of the titanium in the current clinical applications and researches, Ti-6Al-4V's bad processing technology, fatigue, fracture toughness and contain the element of Al&V, which restricted it's application in the field of prosthodontics. Hence, It is necessary to study a new type of titanium alloy for dental restoration with better mechanical properties, corrosion- resistance biocompatibility and easy to process, which can enhance the effect of dental reparation and to expand the indications in the dental restoration.Method:According to alloy design theory and d-electron alloy design theory, additive elements were selected to design the alloy, also considering the requirements of the alloys alloy for dental restoration. The material were processed and distributed as designed. Then it was melted by high vacuum arc furnace, and optimized by aging heat treatment. With the vitodynamics test machines, micro-hardness, metallographic microscope, scanning electron microscopy, X-ray diffraction, and other analytical instruments, the sample's elongation, tensile strength, hardness and other mechanical properties were analyzed, and the alloy morphology, the rule of the changes of elements were observed.Results:1. The designed alloy was Ti-12.5Zr-10Nb-2.5Sn in this experiment, and it was almostα-Ti alloy.2. Cooling rate and metallurgical quality effect a lot to alloy's performance in alloy smelting. In this experiment alloy were prepared with the method of copper Crucible quench high vacuum arc-melting, the advantage of this method were Low-alloy impurities, high purity, smaller loss of alloying elements. The alloy had small crystal, elongation sample showed a tenacity incision, which meaned high tenacity and plasticity.3. The alloy was then taken aging treatment for 1-10 hours under 580℃, It was showed that rigidity increased obviously, modulus of elasticity was tend to raise with the extend of aging treatment. However, the elongation reduced, toughness dimples got smaller and shallow, brittleness increased gradually.4. Analysis showed with the method of copper Crucible quench high vacuum arc-melting,α' phase was get as martensite change occurred. In the process of aging treatment, alloy organization was changed from metastableα' phase to steadyαphase.Conclusions:1. In this paper, considering the biocompatibility, Nb, Zr and Sn, with toxicity-free and better biocompatibility, were selected as the additives, nearlyα-titanium alloy Ti-12.5Zr-10Nb-2.5Sn was designed by the method of copper Crucible quench high vacuum arc-melting. According to the results of the mechanical properties GB test, modulus of elasticity the Titanium alloy in this paper was 126.99GPa, and the alloy's elongation was 8.3%, tensile strength was 848.8Mpa, which met the requirements of prosthodontics.2. Titanium alloy has a lot of Phase structure such asβphase,α' phase and a phase, reasonable heat treatment could be used to regulate the structure which met the performance requirements.3. Copper mold forming was not conducive to bubble getting out. The bug of bubble would effect the alloy's performances such as modulus of elasticity. In order to enhance the performances, the foundry should be improved, appropriate burying material should be chosen or developed to found compact structure alloy. |
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