S. Miyazaki, University of Tsukuba, Tsukuba, Japan; M. H. Cho, M. M. Tomozawa, M. P. J. Buenconsejo, D. H. Y. Kim, University of Tsukuba, Ibaraki, Japan
Ti-Ni based shape memory alloy (SMA) thin films including Ti-Ni, Ti-Ni-Pd, Ti-Ni-Cu, Ti-Ni-Zr, Ti-Ni-Pt and Ti-Ni-Au have been developed utilizing the sputter-deposition method by the present authors’ research group. The Ti-Ni is a standard material and the other ternary alloys have their own attractive characteristics when compared with the Ti-Ni. The Ti-Ni-X (Pd, Zr, Pt, Au) alloys are characterized by high transformation temperatures so that they are expected to show quick response due to higher cooling rates. 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 quick response. The transformation temperature hysteresis and the transformation strain of the R-phase are less than one tenth of those of the martensitic transformation in Ti-Ni, thus the R-phase transformation is also attractive for high response microactuators. The working frequency of the microactuators utilizing the Ti-Ni-Pd and Ti-Ni-Cu thin films reached 100Hz, and that of the microactuator using the R-phase transformation reached 125Hz. Science and technology related topics including crystallization of Ti-Ni amorphous films, interaction between film and substrate, alloying process in Ti/Ni multilayer films will be also reviewed.
Summary: Ti-Ni based shape memory alloy (SMA) thin films including Ti-Ni, Ti-Ni-Pd, Ti-Ni-Cu, Ti-Ni-Zr, Ti-Ni-Pt and Ti-Ni-Au have been developed utilizing the sputter-deposition method by the present authors’ research group. The Ti-Ni is a standard material and the other ternary alloys have their own attractive characteristics when compared with the Ti-Ni. The Ti-Ni-X (Pd, Zr, Pt, Au) alloys are characterized by high transformation temperatures so that they are expected to show quick response due to higher cooling rates. 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 quick response. The transformation temperature hysteresis and the transformation strain of the R-phase are less than one tenth of those of the martensitic transformation in Ti-Ni, thus the R-phase transformation is also attractive for high response microactuators. The working frequency of the microactuators utilizing the Ti-Ni-Pd and Ti-Ni-Cu thin films reached 100Hz, and that of the microactuator using the R-phase transformation reached 125Hz. Science and technology related topics including crystallization of Ti-Ni amorphous films, interaction between film and substrate, alloying process in Ti/Ni multilayer films will be also reviewed.
