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. sin²Ψ' 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.