Investigations of the reduction of NiAl2O4 -: II:: X-ray diffraction studies

The volume shrinkage that accompanies the reduction of NiAl2O4 to a metal-ceramic composite of nickel and alumina leads to residual stress buildup. We have attempted to utilize these stresses to "temper" a ceramic component by placing it under compression. To prove the concept, we produced model specimens which we investigated using X-ray diffraction. Employing the conventional "d vs. sin(2)Psi" method to map surface stresses, the results obtained from these measurements are presented together with finite element calculation predictions used to interpret experimental stress data.