Magnetomechanical damping in Fe–Cr alloys and effect of Al and Mo addition

The damping capacity of ferromagnetic Fe–Cr based alloys containing 0–8% Al and 0–4% Mo has been investigated over a wide range of frequencies and amplitudes using a cantilever device. The resonance curves of the flat beam samples under various driving forces were recorded from which several parameters including the damping capacity (Q-1), delta E effect, internal stress (sigmai) and magnetostriction constant (lambdas), were determined. The variation of these parameters with chemical composition and thermal treatment are analyzed. The results showed that the magnetostriction constant is the key parameter to describe variation of the damping capacity in these alloys. Lower concentration of Al and Mo enhanced the damping capacity several times but higher concentration above 4% decreased it drastically. Addition of Mo resulted in higher damping capacity than did Al.