Analysis and optimization of the magnetomechanical properties of Terfenol-D composites at audio frequencies

The magnetic and magnetostrictive properties of polymer-bonded Terfenol-D rods, compacted from powders with different phenol binder content, are measured in static and dynamic conditions. Magnetic measurements were made up to 40 kHz using a custom made amorphous yoke. Magnetostrictive characterization was performed with prestress up to 15 Mpa in quasi-static and dynamic conditions (up to 40 Hz). A maximum deformation of about 6×10^-4, producing work, can be achieved with a variable phenol content. Dynamic magnetic properties were simulated using the dynamic Preisach model, obtaining an estimate value for conductivity. The inclusion of a non-conductive phenol binder increases the mechanical strength and favors a reduction of eddy current losses, for applications at sonic or ultrasonic frequency