Abstract: The pressure infiltration process is a convenient and inexpensive method for manufacturing cast metal matrix composities. Inherent in the process is the ability to independently control the most important processing parameters such as fiber preform temperature TD, melt temperature T'm infiltration pressure P, and cooling rate, (or solidification time).A deterrent to the use of these materials for structural applications where high specific strength and modulus properties are important are the interfacial reactions between fiber and the matrix which degrade the fiber strength and hence, the com-posity strength. This investigation is primarily concrened with controlling interfacial reactions between P-55 graphite fibers and 1100A1 and Al-0.34%Ti alloys. The effects of processing parameters on these three systems were evaluated. This evaluation included optical and TKM metallography, SEM fraotography as well as mechanical property testing of composite castings and fibers leached from composite castings. The results of these evaluations show that sound composites with high mechanical properties can be produced by at least two routs: (1)control of processing parameters so as to minimize high temperature exposure of the fiber surfaces to molten metal, (2) alloying the matrix with Sior Ti to reduce the activity of carbon in the molten matrix.

Key words: pressure infiltration, interface-reactions, control