Dyachok D. Development of the damage in textured polycrystals of a-iron with the ferrit-martensit structure

Object - sheet polycrystals with a structure of а-iron, a mixture of а-iron (ferrite) and a supersaturated solid solution of carbon in а-iron (martensite). The purpose is to study the connection between the textural state and the anisotropy of the elastic and mechanical properties of sheets with single-phase and two-phase structures of а-iron with the processes of formation and development of damage in the stages of hidden destruction at annealing and deformation. Methods: X-ray diffractometric methods for studying textures on a X-ray device with the construction of straight pole figures, as well as calculation of integral texture characteristics according to the functions of distribution of crystals by orientations; methods of electron microscopy of polycrystal structures on an electron microscope LEO 1455 VP; methods of constructing the deformation-tension curves on the test vehicle Zwick Z100 (100 kN); dynamical method of measuring Young's module in terms of the frequency of its own transverse oscillations of plane samples; numerical mathematical methods for calculating integral texture characteristics according to the distribution of crystal orientation functions. The practical value of the results obtained is the widespread use of the studied low-carbon steels in transport construction. Scientific novelty of the obtained results: 1. Anisotropy of elasticity characteristics, its mean values in various ideal orientations of а-iron was studied. 2. An analytical connection was established between the level of damage of the polycrystal with the bcc structure and the size of the strain strain. 3. The regularities of textural transformations in sheets of two-phase polycrystals with strain strain are established. 4. We obtain the characteristics of elasticity, plasticity and strength of single-phase and two-phase а-iron polycrystals at strain strain. 5. The coefficient of damage of polycrystalline sheets of steel DP600 in the deformed state is determined in relation to the state of equilibrium obtained after long-term annealing. 6. A mechanism of texture transformations in sheet polycrystals with a two-phase structure in the process of tensile deformation is created. 7. The contribution to the anisotropy of the coefficient of damage of microphysical and nano-damage morphology based on the results of electron microscopic fractal analysis was estimated.