Modelling of infiltration of molten metal in fibrous preform by centrifugal force

Infiltration kinetics of molten metal in fibrous preforms by centrifugal force is discussed theoretically. The relationship between the location of infiltration front and time is introduced for three major types of centrifugal casting processes. By the relationship, pressure distribution curves in the preform are also obtained. Some calculated examples are shown for the infiltration of molten aluminum into an alumina short fiber preform. If the speed of revolution is slightly higher than the minimum value determined by threshold pressure, infiltration is continuous. Since the second derivative of the pressure distribution curves in the infiltrated region is always positive and proportional to angular velocity in the centrifugal force field, the pressure curves are convex toward low pressure. When the surface pressure of the preform is low enough or the speed of revolution is high, the region having lower pressure than the threshold pressure appears in the infiltrated region. These results are compared with experimental data from references and by the authors. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.