EFFECT OF PREPARATION CONDITION ON THERMAL EXPANSION ANISOTROPY FOR AMORPHOUS Fe_(78)B_(13)Si_9 ALLOY

The thermal expansion along the longitudinal and transverse directions for amorphous Fe_(78)B_(13)Si_9 alloy prepared under various preparing conditions were investigated.The thermal expansion anisotropy appears in all specimens.The expansion along the longitudinal direction is less than that along the transverse direction.The cooling rate,the melt temperature before jet casting and the cycling temperature affect the thermal expansion coefficients and anisotropy.The amisotropy of thermal expansion originates from the orientation of atomic interaction force,the atomic oscillatory frequency and short range order structure or the directional arrangement of defects in the alloy.