NUMERICAL-SIMULATION OF THE INFILTRATION OF FIBROUS PREFORMS BY A PURE METAL

The numerical simulation of the metal-matrix composites (MMCs) elaboration by an injection process is presented. The equations governing the heat and mass transfers through a porous medium are applied to the metal injection process. The bidimensional numerical model is described based on a finite volume formulation. It is shown that two types of metal solidification appear during the injection: (1) a frontal solidification related to the heat balance between the fibrous preform and the metal and (2) a lateral solidification related to the heat losses toward the mold walls. Numerical tests validate the numerical model in the case of theoretical mono-dimensional geometries when analytical solutions exist. The model is then applied to bi-dimensional geometries. The preform is progressively closed until the channel is obstructed so that injection is achieved to the ''impregnation depth.'' A systematic study determines the influence on the impregnation depth of different parameters, such as thermal properties of fibers and mold walls, injection flow rate, and preform geometry. Finally, the results of the experimental injection of biphenyl resin through the SAFFIL* preform are discussed and compared with the numerical results.