Magnetostrictive Fe82Ga13.5Al4.5 wires with large Wiedemann twist over wide temperature range. (5th December 2017) - Li, Mingming
Abstract: Fe82 Ga13.5 Al4.5 wires of 0.5 mm diameter were successfully prepared by heat forging, rolling, and combining hot and cold drawing. The 〈110〉 texture and A2 phase with 692.3 °C Curie temperature were observed in the as-drawn and 5A alternating current annealed (AC-annealed) wires. A large Wiedemann twist of 222.6″/cm was obtained at 1350 A/m axial magnetic field ( H a ) and 1400 A/m circumferential magnetic field ( H c ) in the AC-annealed wire, which could be attributed to the relatively large magnetostriction of − 46.2 ppm in the perpendicular direction. For displacement sensors application based on the Wiedemann effect at high temperatures, the propagation speed of the torsional wave in Fe82 Ga13.5 Al4.5 wire was studied. A linear downward trend with rising temperature was observed which was related to the decreases in elastic modulus that resulted by thermal expansion. This work shows that Fe82 Ga13.5 Al4.5 wire should be an ideal material for displacement sensors application over wide temperature range; nevertheless, for the measurement accuracy, the velocity of torsional wave should be set consistent with ambient temperature. Graphical abstract: Highlights: Fe82 Ga13.5 Al4.5 wires of 0.5 mm diameter were prepared by heat forging, rolling, and combining hot and cold drawing. A large Wiedemann twist 222.6″/cm was obtained at 1350 A/m axial magnetic field and 1400 A/m circumferential magnetic field. The Wiedemann effect is mainly related to the magnetostriction in perpendicular direction. Fe82 Ga13.5 Al4.5 wire should be an ideal material for sensors application over wide temperature range.