Development of Magnetic Actuator Materials for Energy Harvesting

Magnetostrictive alloys are novel smart materials that exhibit dynamic coupling of magnetic and mechanical properties. The dynamic magnetic-mechanical coupling phenomenon may make magnetostrictive alloys useful for transforming kinetic energy into magnetic energy to be harvested for electrical energy (and vice versa). This offers the potential for magnetorestrictive alloys to be useful for the development of efficient, cost-effective transducer, actuator, smart structure, vibration dampening, and energy harvesting materials for military applications. Several low-cost processing approaches that produce highly textured thin-form magnetorestrictive Fe-Ga alloys were found to be promising for energy harvesting applications. Dalhousie University was contracted to evaluate several techniques for the production of magnetically active alloys and to evaluate the resultant thermal, magnetic, and crystallographic properties of the alloys. This document summarizes the principal results from the final two years of the project, focusing primarily on the development of Fe-Ga magnetorestrictive alloys. Mechanical alloying (via ball milling) and rapid quenching (ribbon casting) were shown to be cost-effective methods for producing Fe-Ga compositions. The magnetic and crystallographic structures were fully characterized and show unique properties. Fe Mossbauer hyperfine fields were shown to be particularly sensitive to atomic scale clustering (as a precurser to ordering). Highly-oriented feedstock Fe-Ga rods were produced using the cost-effective suction extraction method. Fe-Ga rods provided excellent feedstock material that improved the quality (i.e., 100 texture) of DRDC's fabricated Fe-Ga magnetorestrictive wire.
Text in English; Abstract and Executive Summary in English and French.