Редактирование: Crystal: Graz 2012
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In the lecture a review of the models, connecting parameters of macroscopic stiffness tensor of ideal crystals and parameters of interatomic bonds is presented. For description of elastic properties of the atomic bonds three models are considered and compared: central force interaction, multibody interaction, moment interaction. For these models formulae giving explicit connection between macro and micro parameters for a wide range of crystalline structures are given, based on the original works of the authors and literature analysis. | In the lecture a review of the models, connecting parameters of macroscopic stiffness tensor of ideal crystals and parameters of interatomic bonds is presented. For description of elastic properties of the atomic bonds three models are considered and compared: central force interaction, multibody interaction, moment interaction. For these models formulae giving explicit connection between macro and micro parameters for a wide range of crystalline structures are given, based on the original works of the authors and literature analysis. | ||
− | A set of HCP metals with different degree of geometric imperfection (Be, Hf, Cd, Co, Mg, Re, Ti, Zn, Zr) is considered. It is shown that using the moment model leads to more accurate or similar | + | A set of HCP metals with different degree of geometric imperfection (Be, Hf, Cd, Co, Mg, Re, Ti, Zn, Zr) is considered. It is shown that using the moment model leads to more accurate or similar description of the elastic properties than taking into account the deviations in geometrical proportions of real metal's lattice [Krivtsov 2010]. The difference between calculated modulae and experimental data does not exceed the divergence in experimental data from various sourses. Meanwhile, the choice of the interaction depends on the type of the metal electron shell; e.g. ''d''-elements can be described with sufficient accuracy by central force models. Thus, moment interaction is proved to be more universal for HCP structure. |
A number of crystals with covalent preferred bonds are considered. They include diamond type crystals of the carbon group: C, Si, Ge, Sn, and crystals of sphalerite type, such as ZnS (sphalerite), BN, SiC, GaAs, and more then twenty other items. It is shown that moment model of atomic interaction describes with approximately equal precision both diamond and sphalerite type of crystal structures, while the other existing models are mainly orientated to one type of the structure and provide bigger errors or not acceptable for another type. | A number of crystals with covalent preferred bonds are considered. They include diamond type crystals of the carbon group: C, Si, Ge, Sn, and crystals of sphalerite type, such as ZnS (sphalerite), BN, SiC, GaAs, and more then twenty other items. It is shown that moment model of atomic interaction describes with approximately equal precision both diamond and sphalerite type of crystal structures, while the other existing models are mainly orientated to one type of the structure and provide bigger errors or not acceptable for another type. |