Determinations of Residual Thermal Stresses in a SiC‐Al ₂ O ₃ Composite Using Neutron Diffraction

Abstract

Residual thermal stresses and strains, developed during cooling of a SiC whisker‐Al 2 O 3 composite, were determined by an experimental neutron diffraction technique and the results were compared with analytically determined values. High compressive residual thermal stresses were generated in the whiskers during cooldown after sintering. Analytical estimates of the residual stresses were obtained by using two self‐consistent models: (1) a plane strain composite cylinder model and (2) Eshelby's ellipsoidal inclusion theory. The two models gave almost identical estimates of the stresses and strains in the whiskers. The interpretation of the measured strains in the whiskers by neutron diffraction had some uncertainty because of the lack of a clearly defined crystal structure of SiC.