Ti-Ni, Ti-Ni-Pd and Ti-Ni-Cu SMA Sputter-deposited Thin Films and Their Microactuators

Shuichi Miyazaki 

Institute of Materials Science, University of Tsukuba (UT), Tennoudai 1-1-1, Tsukuba 305-8573, Japan


Ti-Ni based shape memory alloy (SMA) thin films including Ti-Ni, Ti-Ni-Pd, Ti-Ni-Cu and Ti-Ni-Zr have been developed utilizing the sputter-deposition method by the present authorユs research group. The Ti-Ni is a standard material and other alloys have their own characteristics when compared with the Ti-Ni. The Ti-Ni-Pd and Ti-Ni-Zr are characterized by high transformation temperatures so that they can be expected to show quick response due to their higher cooling rate. The transformation temperature hysteresis of the Ti-Ni-Pd is narrower than that of the Ti-Ni, while the hysteresis of the Ti-Ni-Zr is wider than that of the Ti-Ni. Thus, the former alloy is more attractive as a microactuator material than the latter alloy. The transformation temperature hysteresis of the Ti-Ni-Cu is less than that of the Ti-Ni without decreasing the transformation temperatures, implying that the Ti-Ni-Cu is also an attractive actuator material for quick response. The transformation temperature hysteresis and the transformation strain of the R-phase of the Ti-Ni are less than one tenth of those of the martensitic transformation, thus the R-phase transformation can be attractive for high response microactuators. In the present presentation, the shape memory characteristics associated with the martensitic transformation of the Ti-Ni, Ti-Ni-Pd and Ti-Ni-Cu and those associated with the R-phase transformation of the Ti-Ni will be shown and the actuator characteristics of microactuators utilizing these thin films will be presented. These alloys can show the stable shape memory effect and superelasticity which are equivalent to those of bulk materials produced by conventional melting methods. Because of the unique microstructures consisting of non-equilibrium thin plate precipitates in the sputter-deposited thin films, they can sometimes show the stable properties even better than the bulk materials. Three types of high-speed diaphragm-type microactuators utilizing the TiNi-based


Presentation: oral at E-MRS Fall Meeting 2005, Symposium C, by Shuichi Miyazaki
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-25 02:04
Revised:   2009-06-07 00:44