High magnetostriction polymer-bonded Terfenol-D composites

Different magnetostrictive composites that contain Terfenol-D particles in a polyurethane elastomer matrix were prepared by changing the ratio of the hard/soft segment (F) of the polyurethane, and modifying the amount of Terfenol-D particles, from 30 to 50 wt%. The magnetostrictive behaviour, as well as the mechanical properties of the magnetic composites, has been investigated. The magnetostriction was measured at room temperature with strain gauges (and parallels) in magnetic fields up to 1 T. The magnetostrictive response improves when the magnetic particles are oriented in different magnetic fields (0.05, 0.5 and 1 T) and reaches ≈700 microstrains for an oriented F = 1 and 50% of Terfenol-D sample. On the other hand, the effect of the matrix on the magnetostrictive response has been examined, obtaining the highest response for a F = 1.5 polyurethane and 50 wt% of Terfenol-D oriented with a magnetic field of 0.5 T.