Developments of new thermo-and magneto-elastic metallic sensor/actuator materials by controlling microstructures by rapid-solidification

Faculty of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan

Abstract

The purposes of this study are to develop fine fiber and foil-type sensor/actuator material elements byusing the originally designed rapid solidification apparatus, and to investigate how to control the microstructures to prepare new multi-functional solid-state metallic sensor/actuator materials. By changing the rotating speed of rapidsolidification roller of either plane surface type or triangle-tip type, the thin foil or fine fiber sensor/actuator material elements can be produced. As the thermoelastic shape memory alloy (TSMA), sharp and non-linear hysteresis TiNiCu and linear and little-hysteresis TiNiCo, both of which function at room temperature range, were developed. As the ferromagnetic shape memory alloy (FSMA), FePd, FePt and CoNiGa with improvement of their ductility have been developed. The magnetostriction in rapid-solidified Fe-29.6at%Pd foil with strong texture of (100) crystal orientation showed 1200 x 10^-6 (= 1200 ppm) strain which is about 40 times larger than that of randomly oriented polycrystalline material. By the same production method, we got very high magnetostriction (400 ppm) and very high ductility (i.e. 180° bending is possible) in Fe-15at%Ga foil.