Development of a thermal stress analysis system for anisotropic single crystal growth

Abstract

We developed a thermal stress analysis system for anisotropic single crystal growth. The analysis system takes account of crystal anisotropy in elastic constants and thermal expansion coefficients and can deal with the thermal stress analyses of five kinds of single crystals, that is, cubic crystal, trigonal crystal, monoclinic crystal, tetragonal crystal and orthorhombic crystal. After calculating thermal stress, we can obtain several stress components for evaluation of macro-cracking and crystal quality such as the maximum principal stress, the Mises equivalent stress and stress components acting on the cleavage plane. This analysis system is combined with a pre- and post-processor code MSC/PATRAN to prepare the input data and to visualize the results. As a numerical example obtained from the present system, the results of thermal stress analyses are shown for a lead molybdate (PMO; PbMoO 4) bulk single crystal that belongs to the tetragonal crystal lattice.