Determination of Strain Distribution Across Jointed Interface of Metals and Ceramics by Laser Speckle Photography

Abstract

The strain distribution across jointed interface of metals and ceramics has been studied by speckle photography, by which a small strain of the order of 10⁻⁴ mm/mm with a gauge length less than 0.5 mm can be detected. Samples of molybdenum/silicon nitride and steel/copper/silicon nitride joints were tested under static compression at room temperature and thermal free-expansion heating up to about 573 K in air. The finite element calculation (FEM) was also made for thermal deformation. As a result, the applicability of speckle photography to determination of strain distribution across jointed interface of metals and ceramics was confirmed, and the results of the thermal strain measurement by speckle photography coincided well with those of thermal deformation analysis by FEM in the region of this study.