Heat treatment at temperatures > 835 degrees C and compressive stresses > 8
0 MPa substantially increased the magnetostrictive performance of Terfenol-
D (Tb0.3Dy0.7Fe1.92) under the condition of zero loading. This heat treatme
nt created a built-in prestress which significantly increased the low stres
s magnetostriction and substantially altered the magnetization curve by red
ucing its initial susceptibility. For measurements at compressive stresses
> 15 MPa the effect of the built-in stress was minimal and the magnetostric
tive performance was not appreciably altered.