Neutron Diffraction Measurements of Thermal Residual Stress of Ceramics Composites
Yoshiaki Akiniwa, Keisuke Tanaka, Nobuaki Minakawa and Yukio Morii
Abstract:he neutron diffraction method was used to measure the residual stress in ceramic composites of alumina mixed with various volume fractions of zirconia, Al2O3/ZrO2, and of silicon carbide, Al2O3/SiC. The thermal residual stresses of the zirconia phase, alumina phase and silicon carbide phase were measured as a function of the volume fraction of constituent phase. The phase stresses were determined from the neutron diffractions of ZrO2 202, Al2O3 113, Al2O3 116 , SiC 220 and SiC 311. In Al2O3/ZrO2 composites, the residual stress in the alumina phase was compression and that in the zirconia phase was tension. On the other hand, in Al2O3/SiC composites, the residual stress in the alumina phase was tension, and increased linearly with the silicon carbide volume fraction. The residual stresses were introduced by the mismatch of the coefficient of thermal expansion. The change of the residual stress with volume fraction of constituent phase agreed well with the theoretical prediction based on Eshelby's inclusion model. Key Words:Residual Stress, Neutron Stress Measurement, X-ray Stress Measurement, Ceramic Composite, Phase Stress, Inclusion Model