Anisotropic thermal expansion behavior of an interpenetrating metal/ceramic composite

Thermal expansion behavior of an interpenetrating metal/ceramic composite having ceramic contents in the range of 34-60 vol.% is studied in this work. Four thermal cycles were carried out between room temperature and 500 degrees C at a constant heating/cooling rate of 5 degrees C/min. Both thermal strain and thermal expansion coefficient decrease with increasing ceramic content in the composite. Evolution of the thermal expansion coefficient with temperature shows anisotropic nature. At all ceramic contents, highest thermal strain and thermal expansion coefficient are obtained along the preform press direction. The extent of thermal expansion anisotropy depends upon both temperature and ceramic content in the composite. The evolution of the observed thermal expansion anisotropy has been attributed to the elastic anisotropy of the preforms and composites, considering as well the elastic-plastic flow behavior of the metallic matrix. The results have been compared with several analytical theoretical models.