CHARACTERIZATION OF LIQUID-METAL INFILTRATION OF A CHOPPED FIBER PREFORM AIDED BY EXTERNAL-PRESSURE .1. VISUALIZATION OF THE FLOW BEHAVIOR OF ALUMINUM MELT IN A FIBER PREFORM

The flow behaviour of an AlSi10Mg alloy melt in Saffil chopped fibre p reforms during liquid metal infiltration aided by squeeze pressure or vacuum has been visualized. Experimental results indicate that under t he external pressure the flow behaviour of the melt in non-wetting cho pped fibre preforms is dominated by capillary laws and the geometrical characteristics of the interspaces between fibres. During the infiltr ation, the melt preferentially penetrated into the large interspaces i n the preform in a manner analogous to flow in a capillary tube networ k. The degree of saturation of the interspaces is dominated by local i nfiltration pressure, and variation of the saturation degree at a give n infiltration depth is determined by fibre distribution uniformity at the microscopic level.