Magnetostriction of Fe–Cr and Fe–Cr–B Alloys

The room temperature magnetostriction of polycrystalline Fe100– x Cr x alloys annealed at 800 °C was investigated as a function of Cr content varying from 10 to 30 at.% Cr. All alloys exhibited a single bcc $\alpha $ -Fe–Cr phase with a disordered A2 structure. With increasing Cr concentration, the grain shape became very elongated. The greatest total magnetostriction value of $70 \times 10^{-6}$ was obtained in the direction of the elongated grains for 30% of Cr. We also investigated the effect of B addition on the magnetostriction and structural properties of the alloy Fe80Cr20. Although the addition of B was expected to form the Fe2B phase, the B-added Fe–Cr alloy forms a ternary phase (Fe z Cr1– z )2B ( $0 ), a weak magnetic phase.