Zero field damping capacity in (TbxDy1-x)Fey

Materials with a large capacity to dissipate mechanical energy are of interest for passive vibration damping. We have measured the zero-field damping capacity of the giant magnetostrictive terbium endash dysprosium endash iron compounds by quasistatic stress endash strain hysteresis loops. The magnetization and strain of the samples were measured for increasing and decreasing compressive stresses, up to 50 MPa. The zero-field, room temperature damping capacity (ΔW/W) was calculated from the stress endash strain loops and is plotted against maximum stress. The damping capacity maximum for the alloy with the nominal Terfenol-D composition occurs at 4.1 MPa with the value 1.75 which corresponds to Q-1=0.28. The damping is almost independent of stress in a multi-phase sample, (Tb0.6Dy0.4)Fe1.4, which contains both Laves phase and elemental rare earth. copyright 1996 American Institute of Physics