Two-Way Shape Memory Effect and Micromachine of Rapidly Solidified Ferromagnetic Fe-Pd Ribbon

Ferromagnetic Fe-Pd alloy is a magneto-thermoelastic actuator material that has a large magnetostriction and the shape memory effect. In order to use the Fe-Pd alloy for a micromachine, we investigated the behavior of the shape memory effect for rapidly solidified Fe-29.6 at% Pd alloy ribbons. From the results, the ribbon exhibited a reversible two-way shape memory effect (TWSME) in the temperature range of 273 to 403 K, where the transformation from the martensite phase to austinite phase is found. On the basis of the development of an actuator of rapidly solidified Fe-29.6 at% Pd ribbon, a small simple-structured micromachine system was fabricated. A wireless micromachine is controlled remotely by an alternating magnetic field: it is able to swim in a fine liquid pipe with the aid of the gripping motion of a small ball. The ball is released by heating it to 340-350 K. This unique fishlike swimming micromachine will be applicable to medical curing devices in the body and as a nondestructive investigation tools for industrial machines and structures.