NiTi形状记忆合金的热电行为

研究了形状记忆合金线的热电行为。当合金线被加热到温度高于其相变温度时，由于相的转变而产生一个大的机械力。将 SMA 线用作驱动器，并研究了不同的参数及它们之间的关系。在不同的压力水平下，这些变化的参数分别是弹性应变(位移)、温度磁滞和电阻。通过传递热模型得到安全的加热电流并预测了相变温度。在自然空气对流的条件下，采用680 mA的电流加热、冷却合金线796 s。在43 MPa的应力水平下，应变恢复率为4.33%，相应的电阻变化为11.2%。在加热、冷却循环过程中，电阻变化与位移和电流分别呈线性关系。该研究有助于精确控制有、无外部传感器反馈的SMA线驱动器。

Thermo-electric behaviour of NiTi shape memory alloy

The thermo-electric behavior of shape memory alloy (SMA) wire was presented. When the wire was electrically heated above its transformation temperature by current, a large mechanical force is exerted due to transformation in its phases. In order to make use of SMA wire as an actuator, different parameters and their relationships were investigated. These parameters are recoverable strain (displacement), temperature hysteresis and electrical resistance variation under different stress levels. Optimum safe heating current was assessed and phase transformation temperatures were estimated by heat transfer model. The wire was heated and cooled by 680 mA of current for 796 s under natural air convection. The strain recovered is 4.33% and corresponding change in resistance is 11.2% at 43 MPa of stress. The resistance variation shows linearly with displacement and current during heating and cooling cycle respectively. This study will be useful in precisely controlling of SMA wire actuator with and without external sensor feedback.