Determination of the strain concentration factors around holes and inclusions in crystals by X-ray topography

Long-range, elastic strains emanating from stress raisers, such as holes and inclusions, were investigated in bent silicon crystals which functioned as a model material. The strains and strain interactions were characterized by X-ray Pendellösung fringe topography and were quantitatively evaluated by X-ray intensity measurements of transverse-oscillation topographs. Improvement of strain measurements were obtained by considering the contribution of anomalous transmission to the intensity measurements and by deposition of an appropriate metal film on the developed topograph to heighten the fluorescence of the silver grains in the emulsion. The strain gradient emanating from a bent specimen containing a hole was experimentally determined and the results were compared to calculations based on continuum mechanics having closed-form solution. Good agreement between experiment and theory was obtained. The dependence of strain interaction on interflaw distance was experimentally demonstrated for specimens containing two holes.