2000 Volume 49 Issue 3Appendix Pages 49-54
The effect of porosity on the elastic constants for X-ray stress analysis in sintered alumina was analyzed on the basis of three micromechanical models: Reuss' model, Voigt's model, and the self-consistent model (SC model). The mechanical Young's modulus decreased with decreasing bulk density or increasing porosity, while Poisson's ratio was nearly constant. The experimental value of X-ray elastic constant, E'X /(1+v'X) (E'X=Young's modulus, v'X=Poisson's ratio), decreased with decreasing bulk density or increasing porosity. SC model gave the best estimation for the effect of bulk density on the X-ray elastic constants. The prediction based on SC model requires the mechanical elastic constants of sintered alumina as a composite and the X-ray elastic constants of diffracting phases. It is not necessary to know the properties of secondary phases. When the mechanical elastic constants of ceramics are not known, the bulk density can be used to estimate the mechanical elastic constants, and then the X-ray elastic constants.
