Composites comprising silicon carbide fibers dispersed in magnesia- aluminate matrix and fabrication thereof and of other composites by sinter forging

摘要

A novel ceramic-ceramic composite of a uniform dispersion of silicon carbide fibers in a matrix of MgOnAl.sub.2 O.sub.3 wherein n ranges from about 1 to about 4.5, said composite comprising by volume from 1 to 50% silicon carbide fibers and from 99 to 50% MgO nAl. sub.2 O.sub.3. The composite is readily fabricated by forming a powder comprising a uniform dispersion of silicon carbide fibers in poorly crystalline phase comprising MgO and Al.sub.2 O.sub.3 in a mole ratio of n and either (a) hot pressing or preferably (b) cold pressing to form a preform and then forging utilizing a temperature in the range of 1100. degree. C. to 1900 C. and a strain rate ranging from about 10. sup. -5 seconds .sup.-1 to about 1 seconds .sup.-1 so that surfaces cracks do not appear to obtain a shear deformation greater than 30%.