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The cordierite based MgO-Al2O3-SiO2 system glass-ceramics is one of new inorganic materials with high mechanical intension, low dielectric dissipation factor, cost and expansion coefficient. It is used in micro-electronic, spaceflight, navigating fields widely.As the same as metal, the mesoscopic system of cordierite based glass-ceramic possess crystal structure, but it also has glass-boundary and pore etc. Research indicates that the crystal phase, glass phase and the quantity or size of grain is important to the material properties, however, the conclusions we have been got are based on isotropy mostly. In fact, cordierite belongs to orthorhombic system, it’s a kind of anisotropic material. The mechanics properties could be influenced by different orientations of different grains, it is hard to obtain the process directly by experimental methods, delightfully, the development of computer and finite element method, proffer a new way for this research.In this paper, we get a plane mesoscopic picture of 43 grains and their expanded grain-boundary from one SEM photograph （the size is about 10 microns） which was made in our laboratory, and then use a software named OOF to change it into some plane finite element models. Afterwards, assign the different grains different crystal orientations （the real orientations can be got used EBSD）, add loads to the selected areas in order to find out the stress-stain influence brought by the elastic stiffness matrix and different thermal expansion coefficients in different orientations. It is showed that, the size of the cordierite grains and the elastic property of their boundary are the most important factor to the tress and thermal-stress distribution, the orientations of different grains influence their mechanics properties slightly, and the position of crack is irrespective about the orientations.
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