Effect of matrix and interface properties on porosity nucleation in metal-matrix composites (Reprinted from Proceedings of Materials Processing Symposium: 1999 ASME International Mechanical Engineering Congress & Exposition, November 14-19, 1999)

The effects are investigated, of matrix alloying, reinforcement coating and cooling condition on porosity nucleation in pressure infiltration casting of metal matrix composites. The threshold fracture pressure is calculated from the work required to sustain a void. The criterion for porosity nucleation is that the magnitude of the local pressure in the casting he less than this fracture pressure. The potential for porosity formation is found to be suppressed through appropriate matrix alloying and reinforcement coating. A careful control of the cooling rate, preform volume fraction, and type and size of reinforcement is also beneficial.