X-Ray Measurement of Triaxial Residual Phase Stress in Zirconia-Alumina Composite Ceramics.

The X-ray diffraction method was used to measure the residual stress in composite ceramics of zirconia mixed with various volume fractions of alumina. The triaxial state of the residual stress in each phase was determined from the X-ray diffractions of Al2O3 (146) by Cu-Kα radiation and of ZrO2 (133) by Cr-Kα radiation. In as-sintered materials, the residual stress in the alumina phase was compression, and decreased linearly with the alumina volume fraction Vf. On the other hand, the tensile residual stress was observed in the zirconia phase, and increased linearly with Vf. Those residual stresses were due to the mismatch of the coefficient of thermal expansion. The theoretical prediction based on Eshelby's inclusion mechanics agreed well with the experimental results.