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Studies on the Precision Casting of NiTi Shape Memory Alloy

NiTi形状记忆合金精密铸造的研究

基本信息

批准号：
62490006
负责人：
HAMANAKA Hitoshi
金额：
$ 0.64万
依托单位：
Tokyo Medical and Dental University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

Ni-Ti alloys which consist of nickel and titanium in nearly equal atomic proportions possess unique mechanical properties, such as shape memory effect and super-elasticity. They are expected a lot of application not only for industrial use but also medical and dental use. As the fabrication of these alloys is so difficult, the precision casting processes are useful where intricate shapes or high dimensional accuracy are required. However, there are a lot of problems in the casting of titanium alloys, because the molten titanium alloys are so reactive, both with the atmosphere and the refractory mold. In this study, the precision casting of NiTi alloys were studied.In the casting machine which we developed, as gas in the mold was removed by heating the mold in the high vacuum, oxidation of metal was less and reaction between alloy and mold was much decreased. NiTi alloys could be cast without losing their important properties, even with commercial dental phosphate bonded silica investme … More nt. The mechanical properties and castability of these alloys are practical and useful in the dental field.The corrosion resistance was much improved by the addition of Au, and the levels of Ni ion concentration released from the alloys decreased considerably compared with those of the original Ni-Ti alloys. The application of NiTi alloy to artificial joints was examined in wear and corrosion tests. The better fitness between NiTi alloy head ball and the hdp socket was obtained than that of commercial femoral head and socket. NiTi alloy is expected to be a promising candidate for artificial joint materials. Ni-Ti alloys showed higher breake down potential in anodic polarization curves than those of commercial Ni-Cr and Co-Cr alloys. The amount of Ni cations dissolved from Ni-Ti alloys in 0.9% NaCl solution is by far lower than those from commercial dental alloys. The properties NiTi alloys were much influenced by the heat treatment condition.The results obtained in this study seem to be useful for industrial, medical and dental field. Less

镍钛合金具有独特的力学性能，如形状记忆效应、超弹性等。预计它们将有大量的应用，不仅用于工业用途，还用于医疗和牙科用途。由于这些合金的制造非常困难，精密铸造工艺在需要复杂形状或高尺寸精度的地方很有用。然而，钛合金的铸造存在许多问题，因为钛合金熔体具有很强的反应性，既与气氛有关，又与耐火材料的结晶器有关。本研究对NiTi合金的精密铸造进行了研究，在自行研制的铸造机上，通过在高真空中加热结晶器，除去了结晶器内的气体，减少了金属的氧化，减少了合金与结晶器之间的反应。即使使用商用牙科磷酸盐结合二氧化硅Invest…，也可以铸造镍钛合金而不会失去其重要性能。更多新台币。这些合金的力学性能和铸造性能在牙科领域是实用的和有用的。添加Au后，合金的耐蚀性大大提高，释放出的Ni离子浓度比原来的Ni-Ti合金显著降低。通过磨损和腐蚀试验，考察了NiTi合金在人工关节中的应用。镍钛合金头球与HDP窝的适合性好于市售股骨头与HDP窝。镍钛合金有望成为人工关节材料的一种有前途的候选材料。在阳极极化曲线上，镍钛合金比商品镍铬和钴铬合金有更高的击穿电位。镍钛合金在0.9%的氯化钠溶液中的镍离子溶出量远低于商品牙科合金。热处理条件对NiTi合金的性能有很大的影响，本研究结果对工业、医疗和牙科等领域具有一定的参考价值。较少