Li Jiheng

Wiedemann effect of Fe—Ga based magnetostrictive wires

(Fe83Ga17)98Cr2 wires each with a diameter of 0.7 mm are prepared by hot swaging and warm drawing from the casting rods directly, because the ductility of Fe83Ga17 alloy is improved by adding Cr element. The Wiedemann twists and dependences on magnetostrictions of Fe83Ga17 and (Fe83Ga17)98Cr2 wires are investigated. The largest observed Wiedemann twists of 245 scm−1 and 182 scm−1 are detected in the annealed Fe83Ga17 and (Fe83Ga17)98Cr2 wires, respectively. The magnetostrictions of the annealed Fe83Ga17 and (Fe83Ga17)98Cr2 wires are 160 ppm and 107 ppm, respectively. The maximum of the Wiedemann twist increases with magnetostriction increasing. However the magnetostriction is just one important factor that affects the Wiedemann effect of alloy wire, and the relationship between magnetostriction and Wiedemann effect is a complex function rather than a simple function.

Effect of yttrium on the mechanical and magnetostrictive properties of Fe83Ga17 alloy

Polycrystalline rod samples of (Fe83Ga17)100–xYx (x=0, 0.16, 0.32, 0.48, 0.64) were prepared by induction melting under argon atmosphere. Effect of yttrium on the mechanical and magnetostrictive properties of Fe83Ga17 alloy was investigated. Small amount of yttrium (0.16 at.%) increased the tensile strength of as-cast Fe83Ga17 alloys to 674 MPa and improved the ductility with elongation of 4.2% at room temperature. The Y2Fe17–xGax (6≤x≤7) phase was formed in the Y-doped Fe83Ga17 alloy since yttrium was hardly dissolved into the α-Fe lattice. Y2(FeGa)17 secondary phase dispersed along the grain boundaries and inside the grains played an important role for the enhancement of mechanical property. The 0.64 at.% Y-doped alloy had magnetostriction of 133 ppm, which was thought to be associated with the alteration of the grain shape and preferential orientation along the axial direction of rods.