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通过真空感应熔炼制备TiNiCuCo形状记忆合金铸锭,然后经锻造、轧制、热拉拔得到准0.5mm的线材,最后对线材进行300~700℃退火。通过拉伸试验和弯曲回复法等研究了不同温度热处理后TiNiCuCo合金的力学性能和形状记忆效应。结果表明:在300~500℃进行热处理,TiNiCuCo合金的抗拉强度和伸长率几乎不发生变化;在600~700℃进行热处理,其抗拉强度显著降低,伸长率显著增大。随着热处理温度的升高,平台应力先减小再增大。在热处理温度为500℃时平台应力最小,为32MPa。平台应变在300~400℃热处理几乎不发生变化,最大值为6.8%。随着热处理温度的升高,平台应变逐渐减小,700℃时平台应变为3.5%。TiNiCuCo合金在300~500℃热处理后具有良好的形状记忆效应;6%~8%弯曲应变后,合金的最大形状回复率可达96%以上。高于500℃进行热处理,合金的最大形状回复率降低。TiNiCuCo合金对温度的响应程度几乎不随热处理温度发生变化。
TiNiCuCo shape memory alloy ingot was prepared by vacuum induction melting, then 0.5mm thick wire was obtained by forging, rolling and hot drawing. Finally, the wire was annealed at 300 ~ 700 ℃. The mechanical properties and shape memory effect of TiNiCuCo alloy after heat treatment at different temperatures were studied by tensile test and bending recovery method. The results show that the tensile strength and elongation of TiNiCuCo hardly change when they are heat-treated at 300-500 ℃. The tensile strength and the elongation of TiNiCuCo alloy decrease with the increase of tensile strength at 600-700 ℃. As the temperature of the heat treatment increases, the stress of the platform first decreases and then increases. When the heat treatment temperature is 500 ℃, the minimum stress of the platform is 32MPa. The strain at 300 ℃ ~ 400 ℃ heat treatment almost unchanged, the maximum value of 6.8%. With the increase of the heat treatment temperature, the strain of the platform gradually decreases, and the strain of the platform is 3.5% at 700 ℃. TiNiCuCo alloy has good shape memory effect after heat treatment at 300 ~ 500 ℃. After 6% ~ 8% bending strain, the maximum shape recovery of TiNiCuCo alloy reaches more than 96%. When the temperature is higher than 500 ° C, the maximum shape recovery rate of the alloy decreases. The response of TiNiCuCo to temperature hardly changes with the heat treatment temperature.