Machining of iron–gallium alloy for microactuator

Abstract

We study the micromachining of iron–gallium alloy for use in a microactuator. Iron–gallium (Galfenol) is an iron-based magnetostrictive material with magnetostriction exceeding 200 ppm, Young's modulus of 70 GPa, and distinctive ductile and machinable properties. An actuator made by small Galfenol component therefore should be simple, robust against external forces and drivable at low voltage. A rod of Galfenol (Fe 81.6Ga 18.4) prepared by the free stand zone melting technique was machined to create pillars of l mm 2 by an ultra precision cutting technique to study the suitability of Galfenol in micro components. Comparison of strain gage measurements for the pillars and non-machined specimens verifies the magnetostriction, with variation arising from the grain distribution that is not significantly dispelled by the milling process. Measurement of displacements by a Laser Doppler vibrometer supports our results and discussion. The successful fabrication of pillars of 0.7 and 0.5 mm 2 and length 5 mm shows the forgiveness of the material under high-speed cutting, and its potential in miniaturization.