Tensile properties of magnetostrictive iron–gallium alloys

Abstract

Iron–gallium alloys can produce magnetostrictions of ∼400 ppm and might function as mechanically robust actuator/sensing materials. Single crystal specimens of Fe-17 at.% Ga were tested in tension at room temperature. Specimens with a [1 1 0] tensile axis orientation exhibited {1 1 0}〈1 1 1〉 slip and an ultimate tensile strength of 580 MPa through 1.6% elongation. The Young’s modulus was 160 GPa in the loading direction with a Poisson’s ratio of −0.37 on the (1 0 0) major face. A specimen with a [1 0 0] tensile axis orientation exhibited {2 1 1}〈1 1 1〉 slip and discontinuous yielding. A maximum tensile strength of 515 MPa was observed with fracture occurring after 2% elongation. The Young’s modulus was 65 GPa in the loading direction with a Poisson’s ratio of 0.45 on the (0 0 1) major face. A sizeable elastic anisotropy of 19.9 was identified for Fe-27.2 at.% Ga accompanied by a Poisson’s ratio of −0.75 to produce a large in-plane auxetic behavior.