J. Japan Inst. Metals, Vol. 56, No. 11 (1992),
pp. 1229-1234

Composition Dependence of Viscosity of Fe-B-Si Liquid Alloy

Tohru Yamasaki¹, Tatuo Shimada¹ and Yoshikiyo Ogino¹

Abstract:

The viscosity of liquid Fe-B-Si alloys has been measured by an oscillating crucible method in the temperature range from melting temperature (T_m) to about 1600 K. The viscosity of these alloys depends strongly on the composition. When the composition is located near a eutectic depression, the viscosity and the activation energies for viscous flow are drastically decreased, e. g., the activation energies obtained are 18.5, 32.2 and 50.9 kJ/mol for Fe_79.5B₁₂Si_8.5 (near eutectic region), Fe₈₁B₁₁Si₈ (hypoeutectic region) and Fe₇₅B₁₅Si₁₀ (hypereutectic region), respectively. This may be due to the existence of some short range orders in the liquid, i. e., when the composition departs from the eutectic, Fe-rich order in the hypoeutectic region and Fe₂B type order in the hypereutectic region are developed. These orders are suspended in the liquid and increase the viscosity and the activation energies. The viscosity below T_m is estimated from the Fulcher relation, i. e., ln η=-3.6582+734.1/(T-674) for Fe_79.5B₁₂Si_8.5 and ln η=-4.1928+1934.1/(T-706) for Fe₇₅B₁₅Si₁₀ where η: poise and T : K.

(Received 1992/06/17)

Keywords:

iron boron silicon alloys, liquid alloy, viscosity, oscillating crucible method, liquid structure

PDF (Free)

Table of Contents

Please do not copy without permission.