Properties Of Inhomogenous Materials With Effect Of Microstucture

Metals are widely used in chemical process equipment. Metals are polycrystalline materials which are aggregates of numerous tiny crystallites. Metal polycrystals often belong to macro homogeneous and meso inhomogeneous materials because of the anisotropy of crystals. Macro-properties of the metal polycrystals depend not only on the chemical and physical properties of their crystallites but also their microstructures which include crystallite orientation distribution, crystallite average size, crystallite average shape, and misorientation among crystallites. With the fabricating technique developing, braided textile composites which have very good strength and flexibility are employed in chemical process equipment.Crystalline orientation distribution in polycrystalline materials can be described by the orientation distribution function (ODF), which can be expanded under the Wigner D- function bases. The expanded coefficients are called the texture coefficients. One can measure these texture coefficients and other microstructure information via modern testing techniques; such as X-ray diffraction, SEM measurements. Hence, it is not only theoretical meanings but also practical values to study the relations between physical and mechanical properties of polycrystalline materials and their microstructures. Until now, there are a lot of papers related to macroscopic elastic and plastic mechanical properties of polycrystalline materials with effects of texture coefficients. However, there are few papers related to physical properties of polycrystals with effects of microstructure. Herein, we study the relations between physical properties of polycrystals and their microstructures. We give a simple and explicit direction-dependent function to express the relations between crystals physical properties (such as: heat expansion coefficients, heat transformation coefficients) and its direction. The direction-dependent function includes the effects of symmetries of crystals. In this paper, we give the direction-dependent function of cubic crystals and 3m crystal. Misorientation among crystallites will affect some properties of polycrystals; such as plasticity. In this paper, we study the misorientation properties and the characteristics, and give the misorientation distribution function (MODF). The MODF includes the effects of crystal's symmetries. The corresponding numerical simulations are presented.For 2-D braided textile composites, we study the method of describing the weaving orientation distribution and derive the macro-constitutive relation of the braided textile composites with effect of the texture. Based on the macro-constitutive relation, the conditions of 2-D braided textile materials are given. Finally, we verify the macro-constitutive relation by ANSYS (A finite element method).