Residual stresses in YAG phase in directionally solidified eutectic Al2O3/YAG ceramic composite estimated by X-ray diffraction

The residual stresses in YAG phase in directionally solidified eutectic (DSE) Al2O3/Y3Al5O12 (YAG) ceramic composite were estimated by XRD. The YAG skeleton specimen without Al2O3 phase, extracted from the composite, was used as a thermally-induced stress-free reference specimen. X-ray stress measurements with Cu Kalpha irradiation were performed on the two planes: parallel and perpendicular to the solidification direction. The estimated average residual stresses were -220 MPa and -157 MPa on the planes parallel and perpendicular to the solidification direction, respectively. The measured residual stresses were described fairly well by a calculation based on a lamellar model under the condition of stress-free temperature 1400-1600 K. 27 refs.