Magnetostriction of Terfenol-D heat treated under compressive stress

Heat treatment at temperatures >835/spl deg/C and compressive stresses >80 MPa substantially increased the magnetostrictive performance of Terfenol-D (Tb/sub 0.3/Dy/sub 0.7/Fe/sub 1.92/) under the condition of zero loading. This heat treatment created a built-in prestress which significantly increased the low stress magnetostriction and substantially altered the magnetization curve by reducing its initial susceptibility. For measurements at compressive stresses >15 MPa the effect of the built-in stress was minimal and the magnetostrictive performance was not appreciably altered.