Neutron diffraction studies of residual stress in alumina/silicon carbide nanocomposites

We have studied the residual stress developed in a number of Al₂O₃/SiC nanocomposites fabricated with a range of different SiC mean particle sizes from 12 to 115nm. These materials were found to have mean matrix stresses in the range 150-200MPa tension and reinforcement stresses of 1.6-1.75GPa in compression. There was no significant dependence of the measured residual stress level on particle size in the range 55-115nm. However, a much larger residual stress was found in the smallest SiC reinforcements. This value may be an artefact of the polymer precursor processing route necessary to fabricate nanocomposites with such a small SiC particle size.