Fracture of composite alumina/yttria-stabilized zirconia joints

Four-point bend tests have been performed on samples consisting of yttria-stabilized zirconia containing 0-80% alumina joined by plastic deformation to the same or different composition. The fracture strength of joints between the same composition was equal to the strength of the monolithic material. Fracture of joints made between different compositions occurred at the position of maximum tensile residual stress, as determined by finite-element analysis, not at the interface. Measured strengths were in accord with fracture mechanics and the calculated residual stresses.