A modified pressure infiltration process was recently developed to synthesize carbon-fiber-reinforced aluminum matrix composites.
In the modified process, the ends of carbon fibers are extended out of the crucible to induce selective cooling. The process
is found to be effective in improving the quality of composites. The present work is focused on determining the effect of
the induced conductive heat transfer on the composite system through numerical methods. Due to the axisymmetry of the system,
a two-dimensional (2-D) model is studied that can be expanded into three dimensions. The variables in this transient analysis
include the fiber radius, fiber length, and melt superheat temperature. The results show that the composite system can be
tailored to have a temperature on the fiber surface that is lower than the melt, to promote nucleation on the fiber surface.
It is also observed that there is a point of inflection in the temperature profile along the particle/melt interface at which
there is no temperature gradient in the radial direction. The information about the inflection point can be used to control
the diffusion of solute atoms in the system. The result can be used in determining the optimum fiber volume fraction in metal
matrix composite (MMC) materials to obtain the desired microstructure.
Manuscript submitted June 14, 2008.