Effect of Dy doping on magnetostrictive and mechanical properties of Fe83Ga17 alloy

Abstract

Fe83Ga17 alloy is a kind of promising magnetostrictive alloys with high magnetostrictive properties and a low saturation magnetic field. As-cast Fe83Ga17Dyx (x=0, 0.05, 0.1, 0.2, 0.4) polycrystalline alloys were prepared by arc melting. Effect of Dy doping on the microstructure, magnetostrictive and mechanical properties of as-cast Fe83Ga17 alloy was investigated. Results show that Dy doped alloys exhibit a dual-phase structure containing the A2 matrix and Dy-rich precipitates (Fe56Ga34Dy10). Both magnetostriction and mechanical properties of Fe83Ga17 alloys are improved by Dy doping. A small amount of Dy addition (x=0.2) significantly causes Fe83Ga17 alloy to transform from typical brittle material (fracture strain ε<1%) to plastic material (ε≈11%). Correspondingly, the fracture mode transforms from intergranular fracture to dimple fracture. At the same time, the ultimate tensile strength and the magnetostriction rise up to 209 MPa and 64 ppm, respectively. Dy-rich precipitates disperse along the grain boundries and inside the grains, which plays an important role in the grain refinement and solution strengthening, and therefore, contribute to the enhancement of mechanical properties of the alloy. The improvement of magnetostriction could be attributed to the large lattice distortion induced by Dy atoms entering into the A2 matrix. Doping Dy into Fe-Ga alloys provides an effective solution to the brittleness in their applications.

Keywords

• fe-ga alloys; dy doping; mechanical properties; magnetostriction