Clarification of Mechanical and Metallurgical Properties of Ti-Ni Shape Memory Alloy Produced by Centrifugal Casting After Self-propagating High-temperature Synthesis

Ti-Ni合金是一种具有形状记忆效应和超弹性的功能材料。这种合金广泛应用于工业和生物医学领域。然而，由于钛镍合金在铸造中存在加工性能差和重力偏析两大问题，几乎所有的应用都局限于作为线材或薄板使用。基于上述观点，本研究采用自蔓延高温合成（SHS）技术制备无重力偏析的Ti-Ni合金铸锭，并尝试采用离心铸造技术制备任意形状的产品。通过系统的实验研究了该方法制备的Ti-Ni合金的力学性能（形状记忆效应、超弹性等）。此外，为了确认这些机械性能，通过差示扫描量热仪（DSC）和X射线衍射（XRD）测量冶金性能（转变温度、结晶度等）。结果表明，采用离心铸造法制备的Ti-Ni合金可用于实际应用，并可实现任意形状的Ti-Ni形状记忆合金制品。

Ti-Ni alloy is a functional material that has shape memory effect and superelasticity. This alloy widely used in industrial and bio-medical fields. However, almost all applications are limited to the use as wire or thin plate, because Ti-Ni alloy has two big problems of little processability and gravity segregation in casting. From above-mentioned point of view, in this research project, we adopted a self-propagating high-temperature synthesis (SHS) for making an ingot of Ti-Ni alloy without the gravity segregation, and tried to a centrifugal casting for making arbitrarily-shaped products. The mechanical properties (shape memory effect, superelastic property, and so on) of Ti-Ni alloy made by this new method were investigated by systematic experiments. Furthermore, in order to confirm these mechanical properties, the metallurgical properties (transformation temperature, crystallinity, and so on) were measured by differential scanning calorimeter (DSC) and X-ray diffraction (XRD). From these results, it was considered that Ti-Ni alloy manufactured by the centrifugal casting after the SHS could be used for practical applications, and that Ti-Ni SMA products with arbitrarily shape were realized by using this method.