Author
Lyudmila Markashova
Bio: Lyudmila Markashova is an academic researcher from National Academy of Sciences of Ukraine. The author has contributed to research in topics: Plasticity & Alloy. The author has an hindex of 2, co-authored 2 publications receiving 32 citations.
Topics: Plasticity, Alloy, Titanium alloy
Papers
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TL;DR: In this paper, the authors provided new experimental data for high-strength VT 22 titanium α+β-type alloy under impact-oscillatory loading and dynamic non-equilibrium process.
Abstract: The purpose of this paper is to provide new experimental data for high-strength VT 22 titanium α + β-type alloy under impact-oscillatory loading and dynamic non-equilibrium process. Based on the performed experimental studies, it was found that overall plastic deformation of this alloy can be increased by a factor 2.75 compared with its initial state without significant loss of strength. To achieve this goal, a new methodology to study the impact behaviour of materials under non-equilibrium process has been used. Physical research revealed that significant microstructural refinement of the alloy is observed after such type of loading, as the result of which the fine grains are formed with subgrain refinement which takes place within the basis of alloy.
23 citations
TL;DR: In this article, the effect of additional force impulse loading on the variation of the initial structure of the aircraft material (alloys D16, 2024-T3, VT22) at various stages of deformation is presented and a significant enhancement of its initial plasticity is achieved.
Abstract: New experimental results on the effect of additional force impulse loading on the variation of the initial structure of the aircraft material (alloys D16, 2024-T3, VT22) at various stages of deformation are presented and a significant enhancement of its initial plasticity is achieved. Complex investigations into the material properties after a dynamic non-equilibrium process made it possible to describe the main regularities in the nature of deformation and fracture of materials, which allowed proposing general recommendations on using the revealed physical and mechanical regularities in the evaluation of strength of aircraft structures.
14 citations
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TL;DR: It is experimentally found that explosive loading leads to an increase in toughness and ballistic resistance of treated materials and the solution to this problem is possible using the energy of high explosives.
Abstract: Technologies for the production of multilayered spherical bottoms and cylindrical shells of quasi-layered material and compaction of the multilayered wall of military equipment elements are developed. The need for these studies is associated with increasing survivability and eliminating fragmentation effects of multilayered structures on manpower and equipment that use pressure vessels (submarines, flamethrower vessels, elements of armored vehicles).Operating conditions for the most efficient use of structures made of layered structural materials are presented. Their advantages in operation and production are described. The highest efficiency is achieved with firm adhesion of structural layers or with the use of quasi-layered materials. The solution to this problem is possible using the energy of high explosives. It is experimentally found that explosive loading leads to an increase in toughness and ballistic resistance of treated materials. Analysis of various methods of multilayered wall compaction is carried out and the most effective technologies are proposed.As a result of the research, process parameters, requirements for process equipment are established.The importance of the presented studies is associated with increasing the fighting efficiency, survivability of military equipment and personnel
51 citations
14 Jan 2019
TL;DR: In this paper, a simple technological method is proposed and tested experimentally, which allows for the improvement of mechanical properties in sheet two-phase high-strength titanium alloys VT23 and VT23M on the finished product (rolled metal), due to impact-oscillatory loading.
Abstract: A simple technological method is proposed and tested experimentally, which allows for the improvement of mechanical properties in sheet two-phase high-strength titanium alloys VT23 and VT23M on the finished product (rolled metal), due to impact-oscillatory loading. Under impact-oscillatory loading and dynamic non-equilibrium processes (DNP) are realized in titanium alloys, leading to the self-organization of the structure. As a result, the mechanical properties of titanium alloys vary significantly with subsequent loading after the realization of DNP. In this study, the test modes are found, which can be used in the production conditions.
18 citations
TL;DR: In this paper, a comparative investigation of fracture envelopes constructed by 3D-DIC and hybrid inverse analyses was conducted for the DP980 1.2t steel over a wide range of loading conditions, tensile tests were conducted using three different specimens that are expected to induce certain stress states of plane strain tension, in-plane shear and uniaxial tension at the potential location for the fracture initiation.
13 citations
30 Mar 2021
TL;DR: The role of the electronic subsystem in the development of the strain-induced phase transformations during ultrasonic impact treatment was discussed in this article, where the molecular dynamics method was applied to demonstrate the mechanism of the phase transformations associated with the formation of stacking faults, as well as the reversible displacement of atoms from their sites in the hcp lattice, causing a change in coordination numbers.
Abstract: Experimental and theoretical studies helped to reveal patterns of surface roughening and the microstructure refinement in the surface layer of commercial pure titanium during ultrasonic impact treatment. Applying transmission electron microscopy technique, a gradient microstructure in the surface layer of the ultrasonically treated sample, where the grain size is varied from nano- to micrometers was revealed. It was shown that the surface plastic strains of the titanium sample proceeded according to the plastic ploughing mechanism, which was accompanied by dislocation sliding, twinning, and the transformations of the microstructure and phase composition. The molecular dynamics method was applied to demonstrate the mechanism of the phase transformations associated with the formation of stacking faults, as well as the reversible displacement of atoms from their sites in the hcp lattice, causing a change in coordination numbers. The role of the electronic subsystem in the development of the strain-induced phase transformations during ultrasonic impact treatment was discussed.
9 citations
23 Nov 2018
TL;DR: In this article, a complex analysis of fractures of high-strength titanium alloy VT23 was performed at the macro and micro levels, and the basic patterns of fracture under static stretching and after the realization of dynamic non-equilibrium processes caused by impact-oscillatory loading and subsequent static stretching were revealed.
Abstract: The complex analysis of fractures of high-strength titanium alloy VT23 was performed at the macro- and microlevels, and the basic patterns of fracture under static stretching and after the realization of dynamic non-equilibrium processes caused by impact-oscillatory loading and subsequent static stretching were revealed. The morphological regularities in the formation of dimples of tearing and alloy stratification at the macro level were established with the help of 3-D profilometry. The micromechanisms of fracture were numerically characterized by the methods of optical-digital analysis, in particular, by highlighting the bound areas, which are the objects of interest—the dimples of tearing. The analysis of the surface of ductile tearing under different loading conditions at the microlevel was performed by analyzing the parameter distribution patterns of the dimples found on it.
8 citations