Refractory materials,for example ceramic materials,initially contain a multitude of defects such as voids,microcracks,grain boundaries etc.Particularly for refractory ceramics being exposed to high temperatures above 1200℃ and loaded by thermal shocks,the macroscopic properties such as effective compliance,strength and lifetime are essentially determined by these microscopic features of the material.The deformation process and failure mechanisms are going along with the creation of new microdefects as well as the growth and coalescence of cracks.