Using the Al-Si-C, Al-Mg-Si-C, Al-Cu-Si-C, and Al-Zn-Si-C phase diagrams, we studied the interaction between the components at interfaces in composite materials based on aluminum and its alloys of various composition with silicon, magnesium, copper, and zinc, which contain particles or fibers of silicon carbide. The formation of the Al4C3 phase depends on the silicon content in the matrix alloy and on the holding temperature; this phase can be revealed using the nonequilibrium polythermal sections constructed in the present study.