Перегляд за Автор "Zavdoveev, A. V."

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Engineering pedagogy course mapping
(SciCell sro, 2022) Рerig, A. V.; Gribkov, E. P.; Gavrish, P. A.; Zavdoveev, A. V.; Mikhieienko, D. Y.; Subotin, O. V.; Razzhyvin, O. V.; Zaliatov, A. F.; Kasian, T. K.; Zhuravlov, M. O.; Davydenko, M. S.; Lodatko, Y. A.; Podlesny, S. V.; Vasylieva, L. V.; Разживін, О. В.
Graduate students of technical universities have practical difficulties with learning and successful instructional implementation of the fundamentals of engineering didactics. The paper is focused on the formulation of a thought-provoking curriculum with computational assignments for the course of “Technical University Pedagogic and Methodological Foundations of Engineering Education” (TUPMFEE) for graduate and Ph.D. students. The paper uses computational modelling of behavioral processes in socio-educational systems. The TUPMFEE-curriculum teaches future engineers to apply computational techniques to modeling of socio-technical phe-nomena. The author-formulated and a computer modeling-supported metaphor forthe psycho-educational effects of high social pres-sure impact on student learning dynamics was allegorically visualized using mechanical rolling stress distribution for the nonlinear social process of student knowledge acquisition during instructor-enhanced education with description of some successive forgetting of the previously acquired instructional material upon the studied course completion. The author-proposed TUPMFEE-course suc-cessfully triggers graduate students’ interest in both social, mechanical and computer sciences.
Shear impact during steel wire drawing on grain boundaries and mechanical properties
(Institute for Metals Superplasticity Problems of Russian Academy of Sciences, 2020) Zavdoveev, A. V. ; Baudin, Т.; Rogante, М.; Pashynska, O. H. ; Skoryk, M.; Пашинська, О. Г.
Shear deformation is one of the effective ways for grain boundary engineering. In the current contribution, the effect of the shear deformation incorporated into the conventional drawing process is shown. A specific feature of this experimental technology is a reduction of the structural anisotropy. This effect is related to the application of dies with shear that makes the metal flow to change its direction. In particular the grain refinement is stronger. The experimental drawing technology results in an extensive increase in the fraction of small grains (less than 3 μm in size) and a decrease in the fraction of large grains. A large amount of small grains with high-angle boundaries in this case is registered. The formation of this kind of grains is explained by progress in competing processes of large grain fragmentation and continuous dynamic recrystallization. The result is the change of the type of the grain boundaries from smooth to serrated ones and the formation of unclosed high-angle grain boundaries. Besides, it has been demonstrated that a certain part of small grains provides grain boundary sliding. The comparative analysis of the hardness tests has demonstrated increasing hardness with deformation accumulation, but after the classical drawing, the hardness grows linearly and stepwise after the experimental shear drawing. The physical reasons of such behaviour are explained by microstructural features which are discussed in current contribution.
Small Angle Neutron Scattering Study of Nanoscale Structure of Low-Carbon Steel After Rolling with Shear Followed by Cold Drawing
(Корейський інститут металів і матеріалів, 2021) Zavdoveev, A. V.; Len, A.; Pashynska, O. H.; Пашинська, О. Г.
Small angle neutron scattering was applied to steel produced by rolling with shear (RS) technology and compared to samples produced by standard technology (ST). Based on small angle neutron scattering measurements the morphology of the grains and pores of RS steels were compared to those of the ST steels. The scattering in small scattering vector region showed anisotropy, attributed to the elongation of the pores; the pearlite lamellae distances along and perpendicular to the rolling directions difered by a factor of 1.5. The results of the Small angle neutron scattering measurements were in accordance with the electrical characteristics of the specimens. They showed smaller and less anisotropic average sizes of the cracks and nanopores for the RS samples than for the ST rods. This confrms the dynamic healing of the nanosized defects during the cold drawing of the RS rods. This fundamental result shows that during severe plastic deformation a cyclic process of nucleation and healing of the nanovoids took place. However, during the standard deformation process only nucleation of the nanovoids is present.