Residual Stress and Grain Deformation in Extruded Polyerystalline BeO Ceramics

Residual strain measurements on a series of sintered BeO tubes indicate that significant stresses developed during processing from the thermal expansion anisotropy. X‐ray topographic studies show that the resulting strains are preferentially located near grain and subgrain boundaries. Fine‐grained samples, 20μ and less, do not show pronounced subgrain structure and exhibit lower dislocation densities in the grain interiors than do coarse‐grained samples.