Effects of residual stresses on mechanical properties of three-layer alumina-based composites

The residual stresses in the layers of three-layered alumina composites with 17.5 vol% zirconia in the inner layer and 40 vol% mullite in the outer layers were studied using X-ray diffraction analysis. The outer layers were under a residual compression while the inner layer was in a state of tension. The residual compressive stress in the outer layers decreased, however the residual tensile stress in the inner layer increased with increasing outer-layer thickness. Due to the existence of residual compressive stresses in the outer layers, three-layer composites were resistant to failure from surface flaws, and therefore expected to be applied under severe contact damage conditions.