nnTemperature dependent deformation localization in irradiated tungsten

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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Dynamic Deformation Behavior of As-Extruded Mg-Gd-Y Magnesium Alloy and the Microstructural Evolution

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.284-286.1579 ◽

2011 ◽

Vol 284-286 ◽

pp. 1579-1583

Author(s):

Ping Li Mao ◽

Zheng Liu ◽

Chang Yi Wang ◽

Feng Wang

Keyword(s):

Magnesium Alloy ◽

Strain Rate ◽

Deformation Behavior ◽

High Strain ◽

Split Hopkinson Pressure Bar ◽

Dynamic Deformation ◽

Strain Rates ◽

Compression Axis ◽

Deformation Localization ◽

Dynamic Deformation Behavior

The dynamic deformation behavior of an as-extruded Mg-Gd-Y magnesium alloy was studied by using Split Hopkinson Pressure Bar (SHPB) apparatus under high strain rates of 102 s-1 to 103s-1 in the present work, in the mean while the microstructure evolution after deformation were inspected by OM and SEM. The results demonstrated that the material is not sensitive to the strain rate and with increasing the strain rate the yield stress of as-extruded Mg-Gd-Y magnesium alloy has a tendency of increasing. The microstructure observation results shown that several deformation localization areas with the width of 10mm formed in the strain rates of 465s-1 and 2140s-1 along the compression axis respectively, and the grain boundaries within the deformation localization area are parallel with each other and are perpendicular to the compression axis. While increasing the strain rate to 3767s-1 the deformation seems become uniform and all the grains are compressed flat in somewhat. The deformation mechanism of as-extruded Mg-Gd-Y magnesium alloy under high strain rate at room temperature was also discussed.

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Some remarks on deformation, localization, and front propagation

Journal of the Mechanical Behavior of Materials ◽

10.1515/jmbm-2012-0032 ◽

2012 ◽

Vol 21 (1-2) ◽

pp. 53-56

Author(s):

George Petsos ◽

Elias C. Aifantis

Keyword(s):

Front Propagation ◽

Deformation Localization

No abstract available.

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An Experimental Study on Stretchy and Tough PDMS/Fabric Composites

Journal of Applied Mechanics ◽

10.1115/1.4041679 ◽

2018 ◽

Vol 86 (1) ◽

Cited By ~ 4

Author(s):

Ruofei Chang ◽

Zhou Chen ◽

Cunjiang Yu ◽

Jizhou Song

Keyword(s):

Fracture Toughness ◽

Low Cost ◽

Elastic Response ◽

Deformation Localization ◽

Practical Applications ◽

Damage Propagation ◽

Linear Elastic ◽

Nylon Fabric ◽

Fabric Composite ◽

Fabric Composites

Polydimethylsiloxane (PDMS) has a good elasticity but with a pretty low fracture toughness, which limits its use in practical applications. This paper presents a simple and low-cost approach to manufacture a PDMS/fabric composite through incorporating the commercially available stretchy plain weft-knitted nylon fabric into the PDMS matrix. The fracture toughness of the composite is much higher than that of pure PDMS with an increase up to 700%. The toughening mechanism, which can be attributed to the deformation localization induced fiber stretch and damage propagation in the PDMS matrix, is fully investigated. During cyclic loadings, the composite may exhibit a linear elastic response or a significant hysteresis depending on the stretch level. These results provide physical insights into the deformation mechanism of a soft fabric-reinforced composite and may offer practical routes to realize robust crack-insensitive PDMS.

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

PNRPU Mechanics Bulletin ◽

10.15593/perm.mech/2021.1.03 ◽

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.

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Structural-Phase State, Mechanical Properties, Acoustic and Magnetic Characteristics in the Sustainable Deformation Localization Zones of Power Equipment Made of Structural and Heat Resistant Steels

Metals ◽

10.3390/met11101638 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1638

Author(s):

Nikolay Ababkov ◽

Alexandr Smirnov ◽

Vladimir Danilov ◽

Lev Zuev ◽

Natalya Popova ◽

...

Keyword(s):

Mechanical Properties ◽

Phase State ◽

Structural Phase ◽

Magnetic Characteristics ◽

Internal Stresses ◽

Power Equipment ◽

Deformation Localization ◽

Structural Phase State ◽

Heat Resistant ◽

Heat Resistant Steels

The paper presents the results of the analysis of the microstructure, mechanical properties, acoustic and magnetic characteristics of the metal of pipelines that are part of heat and power equipment, after long-term operation, made of structural and heat-resistant steels in the zones of localization of plastic deformation. Samples of 0.2 С steel and 0.12С-1Сr-1Mo-1V steel were studied in the initial state, as well as after operation for 219 and 360 thousand hours, respectively. As a result of the studies carried out for each sample, the phase composition was determined (qualitatively and quantitatively), and the following parameters of the fine structure were calculated: volume fractions of structural components of steel (pearlite and ferrite), scalar and excess ± dislocation density, curvature-torsion of the crystal lattice χ, amplitude of internal stresses (shear stress and long-range stresses). All quantitative parameters of the structure are determined both in each structural component of steel, and in general for each sample. The structure of the metal of all specimens after deformation before the formation of zones of stable localization of deformations consists of a ferrite-pearlite mixture, and for specimens after operation before fracture only of unfragmented and fragmented ferrite. Ferrite, which occupies the bulk of the material, is present both unfragmented and fragmented. For all samples, the ratios ≥ , χ = χpl, σL ≥ σd were calculated, which indicate whether there is a danger of the initiation of microcracks in metal samples. For specimens without operation and after operation without damage in zones of stable localization of deformations, these conditions are met, and for specimens after operation until destruction, they are not met. It was found that the structural-phase state in the zones of localization of deformations has a direct effect on the characteristics of non-destructive tests. Thus, for all investigated samples, the values of such parameters as the delay time of the surface acoustic wave, the attenuation coefficient, the amplitude of the received signal, and the intensity of magnetic noise in the zones of deformation localization were established.

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Mechanisms of deformation localization and mechanical twinning under the conditions of phase instability of a crystal in stress fields

Russian Physics Journal ◽

10.1007/s11182-005-0003-7 ◽

2004 ◽

Vol 47 (8) ◽

pp. 818-839 ◽

Cited By ~ 1

Author(s):

A. N. Tyumentsev ◽

A. D. Korotaev ◽

Yu. P. Pinzhin ◽

I. Yu. Litovchenko ◽

N. S. Surikova

Keyword(s):

Mechanical Twinning ◽

Stress Fields ◽

Deformation Localization ◽

Phase Instability ◽

Mechanisms Of Deformation

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Shear band propagation in honeycombs: numerical and experimental

Rapid Prototyping Journal ◽

10.1108/rpj-06-2016-0098 ◽

2018 ◽

Vol 24 (2) ◽

pp. 477-484

Author(s):

Hossein Goodarzi Hosseinabadi ◽

Reza Bagheri ◽

Volker Altstädt

Keyword(s):

Finite Element ◽

Shear Band ◽

Energy Absorption ◽

Image Correlation ◽

Correlation Technique ◽

Deformation Localization ◽

Content Type ◽

Fused Deposition ◽

Absorption Potential ◽

3D Printed

Purpose Hexagonal honeycombs with meso-metric cell size show excellent load bearing and energy absorption potential, which make them attractive in many applications. However, owing to their bend-dominated structure, honeycombs are susceptible to deformation localization. The purpose of this study is to provide insight about shear band propagation in struts of 3D-printed honeycombs and its relation to the achieved macroscopic mechanical behavior. Design/methodology/approach Hexagonal honeycombs and unit cell models are 3D-printed by fused deposition modeling (FDM). The samples are exposed to compression loading and digital image correlation technique and finite element analyses are incorporated. Findings It is found that the strain contours, which are obtained by finite element, are in agreement with experimental measurements made by DIC. In addition, three stages of shear band propagation in struts of 3D-printed honeycombs are illustrated. Then the correlation between shear band propagation stages and the achieved macroscopic mechanical responses is discussed in detail. Originality/value For the first time, a hierarchical activation of different modes of shear band propagation in struts of a 3D-printed honeycomb is reported. This information can be of use for designing a new generation of honeycombs with tailor-made localization and energy absorption potential.

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