铝/氧化铝纤维预制体的液态浸渗动力学

KINETICS OF INFILTRATION OF LIQUID ALUMINIUM INTO ALUMINA FIBROUS PREFORM

在将纤维预制体当作“毛细管束”并假定浸过它的液态金属流为层流的基础上，采用达西定律，对液态金属向纤维预制体的浸渗动力学进行了理论分析。针对Ａｌ１．５Ｍｇ合金／氧化铝短纤维复合材料系，进行了浸渗动力学实验研究。结果表明：浸渗过程的启动，需要有一定的孕育时间。对于外加浸渗压力为常量的浸渗过程，浸渗深度随浸渗时间的变化为抛物线关系；浸渗速度的大小可由所导出的关系式较好地预测，外加浸渗压力大小对孕育时间和浸渗速率有很大的影响。

The infiltration kinetics of liquid metal into a fibrous preform was theoretically analyzed on the basis of Darcy's law and the assumptions that the porous preform is treated as “bundles of capillaries” and that the liquid flow penetrating the preform is considered to be laminar. Experiments for infiltration kinetics study were carried out with respect to an Al 1.5Mg aluminium alloy/alumina short fiber preform system. It was revealed that an incubation time is required to activate infiltration, that there is a parabolic dependence of the infiltrated depth on the infiltration time for infiltration process under the constant external pressure, and that the infiltration rate can be well predicated by the derived equation and the proposed theoretical model. Both the incubation time and the infiltration rate are significantly influenced by the applied pressure.