【摘要】 TiNi形状记忆合金由于其优良的合金性能,而成为商业化应用最为广泛的形状记忆合金。利用25 kg级自制BaZrO₃坩埚制备了49.3Ti-Ni （at%）合金,并将铸态合金加工成为直径为1 mm的丝材。利用XRD、氮氧化物分析仪等分析测试手段对合金的化学成分及物相组成进行研究分析,利用扫描电镜、光学显微镜对合金的显微组织进行观察,利用两台自制设备对合金丝材的形状记忆回复率及疲劳性能进行分析测试。实验结果表明,利用BaZrO₃坩埚对制备的钛镍合金的氧、氮含量能够分别达到560和17μg/g,杂质元素含量满足ASTM对于医用植入物以及医疗器械的标准要求;相对真空电弧熔炼,利用BaZrO₃坩埚感应熔炼制备的TiNi合金化学成分更加准确均匀;与石墨坩埚感应熔炼相比,利用BaZrO₃坩埚制备的TiNi合金丝材表现出更为优良的形状记忆回复率和抗疲劳性能,其形状记忆回复率在550℃保温20 min淬火后,变形量为2%时能够达到98.62%,其疲劳性能在500℃保温20 min淬火后能够达到3072次。更多还原

【Abstract】 TiNi shape memory alloy（SMA） is one of the commercially successful shape memory alloys（SMAs） due to its excellent performances. The 49.3 Ti-Ni（at%） alloy was prepared by vacuum induction melting in a 25 kg-grade home-made BaZrO₃ crucible, and the alloy ingot was turned into wire form（Ф1.0 mm）. The chemical compositions（including oxygen, nitrogen and carbon） of the as-cast alloy were measured and the phase constitution was analyzed by X-ray diffraction（XRD）. The microstructures were observed by optical microscope（OM） and scanning electron microscope（SEM）, and the shape memory recovery rate and fatigue life of alloy wires were tested by two home-made test apparatus, respectively. Experimental results show that the contents of oxygen and nitrogen in the alloy ingot are 560 and 17 μg/g, respectively, and the impurity contents in TiNi alloy melted using the BaZrO₃ crucible are just eligible to medical devices and surgical implants. The TiNi alloy chemical composition has a more uniform and accurate melted using BaZrO₃ crucible than alloy prepared by the vacuum arc remelting（VAR）, and has a higher shape memory recovery rate and fatigue life than the alloy melted using graphite crucible. The best shape memory recovery rate can reach 98.62% under 2% deformation after aging at 550 °C for 20 min and water quenching, and the best average fatigue life can reach 3072 times after aging at 500 °C for 20 min and water quenching,.更多还原