TiNi基形状记忆合金薄膜的相变特征研究

利用磁控溅射的方法在单晶Si和非晶SiO2基片上制备了TiNi和TiNiCu形状记忆合金薄膜,并利用示差扫描量热法和基片曲率法研究了薄膜的相变特征及应力随温度的变化.研究结果表明450℃溅射形成的记忆合金薄膜具有良好的形状记忆效应,在微电子机械系统有很好的应用前景.TiNi薄膜降温时出现R相变,因而发生两步相变,而TiNiCu薄膜中马氏体和奥氏体间直接转变.基片以及薄膜成份对相变点有很大的影响.单晶Si片作为基片时,记忆合金薄膜和基片间有很好的结合力,而SiO2作为基片时,记忆合金薄膜容易剥落.

Phase Transformation Behavior of TiNi Based Shape Memory Alloy Films

In this work,TiNi and TiNiCu shape memory alloy films on Si and SiO_2 substrate were successfully prepared by co-sputtering of TiNi target with a separated Cu and Ti target.The transformation behavior and stress as a function of temperature were investigated by differential scanning calorimeter(DSC) and curvature measurement methods.The results showed that the shape memory alloy film has a good shape memory effect,which was a promising candidate material for micro-electric mechanical system.For TiNi shape memory alloy film,two-stage transformation was observed,corresponding to transformations among austensite,R-phase and martensite phase.However,austensite transforms into martensite directly for TiNiCu film.The substrate and the composition of the film had a prominent effect on the transformation temperatures.The film had a good adherence on the Si substrate and is easy peeled from the SiO_2 substrate.