scholarly journals Kinetics of Plastic Deformation Localization Bands in Polycrystalline Nickel

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1440
Author(s):  
Svetlana A. Barannikova ◽  
Mikhail V. Nadezhkin
Keyword(s):  
Plastic Deformation ◽  
Constant Strain Rate ◽  
Correlation Method ◽  
Deformation Bands ◽  
Total Deformation ◽  
Polycrystalline Nickel ◽  
Deformation Localization ◽  
Jerky Flow ◽  
Time Period ◽  
Localized Plastic Deformation

Jerky flow has recently aroused interest as an example of complex spatiotemporal dynamics resulting from the collective behavior of defects in Al- and Mg-based alloys under loading. This paper presents the results of the study of the macroscopic strain localization kinetics in Nickel 200 (99.5 wt % purity). Uniaxial tension of flat samples is monitored at room temperature in the load–unload mode at a constant strain rate and total deformation increment up to 5%. The stress–strain curves reveal jerky flow from the yield point to the formation of the neck. The digital speckle correlation method evidences the movement of localized plastic deformation bands under the conditions of the Portevin–Le Chatelier effect (PLC). It is shown that stress drops during jerky flow in Ni are accompanied by the formation of morphologically simple single PLC bands. It is established that, with an increase in total deformation, the number of PLC bands and their velocity of motion along the sample decrease, while their time period increases. Moreover, an increase in total deformation leads to an increase in the parameters of the force response (i.e., time period and stress drop magnitude). It is found that the criterion of damage for PLC bands as a function of the total strain has a sigmoidal shape.

scholarly journals Studying Deformation Behaviors in Austenitic Stainless Steels within a Temperature Range of 143 K < T < 420 K

2021 ◽  
pp. 22-30
Author(s):  
S. A Barannikova ◽  
A. M Nikonova ◽  
S. V Kolosov
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Localization ◽  
Work Hardening ◽  
Deformation Localization ◽  
Linear Hardening ◽  
Jerky Flow ◽  
Temperature Range ◽  
Α Phase ◽  
Flow Stage

This work deals with studying staging and macroscopic strain localization in austenitic stainless steel 12Kh18N9T within a temperature range of 143 K < T < 420 K. The visualization and evolution of macroscopic localized plastic deformation bands at different stages of work hardening were carried out by the method of the double-exposure speckle photography (DESP), which allows registering displacement fields with a high accuracy by tracing changes on the surface of the material under study and then comparing the specklograms recorded during uniaxial tension. The shape of the tensile curves σ(ε) undergoes a significant change with a decreasing temperature due to the γ-α'-phase transformation induced by plastic deformation. The processing of the deformation curves of the steel samples made it possible to distinguish the following stages of strain hardening, i.e. the stage of linear hardening and jerky flow stage. A comparative analysis of the design diagrams (with the introduction of additional parameters of the Ludwigson equation) and experimental diagrams of tension of steel 12Kh18N9T for different temperatures is carried out. The analysis of local strains distributions showed that at the stage of linear work hardening, a mobile system of plastic strain localization centers is observed. The temperature dependence of the parameters of plastic deformation localization at the stages of linear work hardening has been established. Unlike the linear hardening, the jerky flow possesses the propagation of single plastic strain fronts that occur one after another through the sample due to the γ-α' phase transition and the Portevin-Le Chatelier effect. It was found that at the jerky flow stage, which is the final stage before the destruction of the sample, the centers of deformation localization do not merge, leading to the neck formation.

Evolution of Macro-Scale Plastic Flow Localization of Tri-Layered Stainless Steel - Low Carbon Steel - Stainless Steel Metal with Digital Image Correlation Method

2016 ◽  
Vol 870 ◽  
pp. 60-65 ◽  
Author(s):  
S.A. Barannikova ◽  
Lev B. Zuev ◽  
A.V. Bochkareva ◽  
A.G. Lunev ◽  
Yu.V. Li ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Carbon Steel ◽  
Digital Image Correlation ◽  
Plastic Flow ◽  
Low Carbon Steel ◽  
Correlation Method ◽  
Image Correlation ◽  
Low Carbon ◽  
Localized Plastic Deformation

Evolution of localized plastic deformation in tri-layered metal material casting consistng of the working part (layer) from austenitic stainless steel and bearing part from low-carbon steel was investigated. The pictures of localization of the plastic flow during the process of uniaxial tension were obtained by means of the digital image correlation method (DIC). Using optical microscopy methods, the changes in the fracture surface were investigated. The deformation diagrams were examined for deformed samples of tri-layered metal. These were found to show all the plastic flow stages: the linear, parabolic and pre-failure stages would occur for the respective values of the exponent n from the Lüdwik-Holomon equation. The analysis of the plastic flow stages and localized plastic deformation parameters was performed.

scholarly journals Analysis of Plastic Flow Localization in Bimetal Electrolytically Saturated with Hydrogen

2018 ◽  
Vol 7 (2.23) ◽  
pp. 475
Author(s):  
S Barannikova ◽  
Yu. Li ◽  
A Malinovskiy ◽  
L Zuev
Keyword(s):  
Plastic Deformation ◽  
Electrochemical Cell ◽  
Correlation Method ◽  
Image Correlation ◽  
Low Carbon ◽  
Plastic Yielding ◽  
Flow Localization ◽  
Hydrogen Saturation ◽  
Electrolytic Hydrogenation ◽  
Localized Plastic Deformation

Plastic deformation of bimetal compound of austenitic stainless and low-carbon construction steels, resistant to corrosion, is localized through the digital image correlation method upon the uniaxial tension of sample. The evolution of zones of plastic deformation in bimetal is inspected upon the onset of the process and is exposed to hydrogen saturation in a three-electrode electrochemical cell at a controlled constant cathode potential for 6 hours. Localized plastic deformation zones are found to form and evolve during the tension of bimetal samples both at the onset and after 6 hour of the electrolytic hydrogenation throughout the plastic yielding in the primary, protective and transitional layers of the bimetal. The bimetal fracture is initiated by stress concentrated in the bimetal transition layer. Nucleation and propagation of a crack is observed at early work-hardening stages. The fracture of bimetal after hydrogenation is established to be more ductile as compared with precursor.  

scholarly journals Microstructure and Texture of Hydrostatic Extrusion Deformed Ni Single Crystals and Polycrystal

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
D. Jakubowska ◽  
J. Zdunek ◽  
M. Kulczyk ◽  
J. Mizera ◽  
K. J. Kurzydłowski
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Single Crystal ◽  
Single Crystals ◽  
Relevant Literature ◽  
Hydrostatic Extrusion ◽  
Total Deformation ◽  
Polycrystalline Nickel ◽  
Before And After

The differences in the microstructure and texture of two Ni single crystals, with different initial orientations (100and110), and of polycrystalline nickel, before and after severe plastic deformation (SPD) produced by hydrostatic extrusion (HE), have been investigated. The crystals were deformed by a two-step HE process with a total deformation value ofε=1.2. The global texture, mechanical properties, and microstructure were examined after the deformation. In every investigated sample, the presence of111fibre texture was noted, while the starting orientation of a100Ni single crystal was preserved in 50% of the volume. The results obtained were compared with the relevant literature data.

The Effect of Grain Boundary State on Deformation Process Development in Nanostructured Metals Produced by the Methods of Severe Plastic Deformation

2011 ◽  
Vol 683 ◽  
pp. 69-79 ◽  
Author(s):  
Evgeny V. Naydenkin ◽  
Galina P. Grabovetskaya ◽  
Konstantin Ivanov
Keyword(s):  
Plastic Deformation ◽  
Grain Boundary ◽  
Severe Plastic Deformation ◽  
Deformation Process ◽  
Process Development ◽  
Grain Boundary Sliding ◽  
Total Deformation ◽  
Nanostructured Metals ◽  
Boundary State ◽  
Boundary Sliding

In this review the investigations of deformation process development are discussed which were carried out by tension and creep in the temperature range Т<0.4Tm (here Тm is the absolute melting point of material) for nanostructured metals produced by the methods of severe plastic deformation. The contribution of grain boundary sliding to the total deformation in the above temperature interval is also considered. An analysis is made of the effect of grain size and grain boundary state on the evolution of grain boundary sliding and cooperative grain boundary sliding in nanostructured metals.

Effect of Hydrogen on the Development of Superplastic Deformation in the Submicrocrystalline Ti–6Al–4V Alloy

2016 ◽  
Vol 838-839 ◽  
pp. 344-349 ◽  
Author(s):  
Galina P. Grabovetskaya ◽  
Ekaterina N. Stepanova ◽  
Ilya V. Ratochka ◽  
I.P. Mishin ◽  
Olga V. Zabudchenko
Keyword(s):  
Solid Solution ◽  
Plastic Deformation ◽  
Flow Stress ◽  
Superplastic Deformation ◽  
Deformation Localization ◽  
Solid Solution Strengthening ◽  
Solution Strengthening ◽  
Hydrogenation Effect

Hydrogenation effect on the development of superplastic deformation in the submicrocrystalline Ti–6Al–4V alloy at temperatures (0.4–0.5)Тmelt is investigated. Hydrogenation of the submicrocrystalline Ti–6Al–4V alloy to 0.26 mass% during superplastic deformation is found to result in solid solution strengthening, plastic deformation localization, and as a consequence, decrease of the deformation to failure. Possible reasons for the decrease of the flow stress and increase of the deformation to failure in the submicrocrystalline Ti–6Al–4V–0.26H alloy during deformation under conditions of superplasticity and simultaneous hydrogen degassing from the alloy are discussed.

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