Dislocation generation due to differences between the coefficients of thermal expansion

There have been several investigations of the elastic stresses and strains generated about an inclusion, which has a coefficient of thermal expansion different from that of the matrix, as a result of heating or cooling. Also, there have been a few investigations of the magnitude of the plastic strain and the plastic zone under the above conditions wherein the plastic deformation induced by the difference between the thermal expansion coefficients was treated in a continuum manner. Since individual dislocation motion was not considered, the dislocation arrangement and densities cannot be specified by the above-mentioned investigations. Therefore, an in situ transmission electron microscopy investigation was undertaken of dislocation generation at the inclusions due to the differential thermal contraction. A simple model based on prismatic punching was developed to account for the relative dislocation density due to the differential thermal contraction.