Synthesis of Tb0.3Dy0.7Fe1.9 magnetostrictive alloy by unidirectional solidification in magnetic field and microgravity

We performed unidirectional solidification experiments on magnetostrictive materials of Tb0.3DY0.7Fe2-x, (Terfenol-D) alloy in a static magnetic field from 0 to 0.1 T and microgravity of 10(-4) g for 10 s. When the magnetic field strength was increased from 0 to 3.7 x 10(-2) T during unidirectional solidification in microgravity, a [1 1 1] crystallographic alignment of the grains dominated, and the maximum magnetostriction increased from 500 to 2000 ppm. However, when a magnetic field above 3.7 x 10(-2) T was applied during solidification, magnetostriction decreased to 1000 ppm because cracks were formed. For comparison, unidirectional solidification under field of 3.7 x 10(-2) T in normal gravity yields a maximum magnetostriction of 1000 ppm. (C) 2002 Elsevier Science B.V. All rights reserved.