Dense, shaped ceramic/metal composites at <= 1000 degrees C by the displacive compensation of porosity (DCP) method

The Displacive Compensation of Porosity method for fabricating dense, shape d ceramic/metal composites at modest temperatures is demonstrated, In this process, liquid-metal/solid-ceramic displacement reactions are used to gene rate more ceramic (by volume) than is consumed, so that pores within a cera mic preform can be filled with the new ceramic phase (i.e,, densification w ithout sintering). Dense, lightweight MgO/Mg-Al composites (74-86 vol% oxid e) and higher-melting, co-continuous MgAl2O4/Fe-Ni-Al-bearing composites (4 2-59 vol% oxide) have been produced via the pressureless infiltration and r eaction of magnesium-bearing liquids with porous preforms of Al2O3 and NiAl 2O4+Fe, respectively, at temperatures of 900 degrees-1000 degrees C, The co mposites are relatively tough and retain the shapes and dimensions (to with in a few percent) of the starting preforms.