医用镍钛管永久变形量影响因素的研究

使用医用镍钛管制备拉伸试样，研究了时效温度、时效时间、循环加载次数、应变和加载速率对医用镍钛材料永久变形量的影响。结果表明：随着时效温度的升高，试样的永久变形量先增大后减小；随着时效时间的延长，试样的永久变形量增大；460 ℃时效30 min时，试样的永久变形量增加到3.350%；随着加载次数的增加，累积永久变形量逐渐增大，直至一定次数后趋于稳定；当应变不超过8%时，永久变形量较小（<0.100%）；但随着应变增大至15%时，永久变形量增加到8.350%；随着加载速率的增加，试样的永久变形量增大。对镍钛材料永久变形量影响较大的因素分别为时效温度、时间和应变。

Study on the Influencing Factors for Permanent Set of Medical Nitinol Tube

Medical nitinol tube was used to prepare tensile specimen, and the effects of aging temperature, aging time, cyclic loading number, loading strain, and loading rate on the permanent set of medical nitinol were studied. The results indicate that with the increase of aging temperature, the permanent set of specimen first increases and then decreases. With the increase of aging time, the permanent set of specimen increases. After aging at 460 °C for 30 min, the permanent set of specimen increases to 3.350%. With the increase of loading number, the cumulative permanent set increases gradually and tends to be stable after a certain number. As the strain is less than 8%, the permanent set is quite small (<0.100%). However, when the strain increases to 15%, the permanent set increases to 8.350%. With the increase of loading rate, the permanent set of specimen increases. The aging temperature, time and strain have great influences on the permanent set of nitinols.