Solidification of infiltrated metal matrix composites

Abstract

This paper describes one portion of a broad continuing program at Massachusetts Institute of Technology on metal matrix composites. It deals with solidification of fibrous composites during and after infiltration The fibers influence solidification in important ways by restricting the maximum size to which a dendrite arm can grow by "ripening". More remarkably, the dendritic structure in composites is completely eliminated at longer solidification times, as a result of "coalescence " and of enhanced solid diffusion. The result is that substantially more homogeneous structures can be obtained in metal-matrix composites than in usual castings and ingots.