Characterization of High-Speed Microactuator Utilizing Shape Memory Alloy Thin Films

Dynamic actuation properties of two types of high-speed microactuators utilizing Ti-Ni-based thin films were investigated. One type is a microactuator utilizing a Ti-Ni-Pd thin film which has high transformation temperatures. Cooling rate of a microactuator increases with increasing temperature difference between transformation and atmosphere temperatures, thus the increase in transformation temperature is effective to increase the actuation response. The other type is a microactuator using R-phase transformation of a Ti-Ni thin film which has a narrow transformation temperature hysteresis. The narrow transformation temperature hysteresis of the R-phase transformation is effective to increase the actuation response. Both types of actuators are promising for high response applications. The working frequency of the microactuators reached 100Hz in the two types of microactuators utilizing the martensitic transformation of the Ti-Ni-Pd thin film and the R-phase transformation of the Ti-Ni thin film.