ZERO-FIELD DAMPING CAPACITY IN (TBXDY1-X)FE-Y

Materials with a large capacity to dissipate mechanical energy are of interest for passive vibration damping. We have measured the zero-fiel d damping capacity of the giant magnetostrictive terbium-dysprosium-ir on compounds by quasistatic stress-strain hysteresis loops. The magnet ization and strain of the samples were measured for increasing and dec reasing compressive stresses, up to 50 MPa. The zero-field, room tempe rature damping capacity (Delta W/W) was calculated from the stressstra in loops and is plotted against maximum stress. The damping capacity m aximum 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 damp ing is almost independent of stress in a multi-phase sample, (Tb0.6Dy0 .4)Fe-1.4, which contains both Laves phase and elemental rare earth. ( C) 1996 American Institute of Physics.