Mesoscale Deformation-Induced Surface Phenomena in Loaded Polycrystals

Романова, В. А.; Балохонов, Р. Р.; Zinovieva, O.

doi:10.22190/fume210102006r

Cited by 5 publications

(3 citation statements)

References 32 publications

(58 reference statements)

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“…For iron, the down-break in the Hall-Petch relationship may occur for small nanograin sizes such as 30 nm, but, even in nanograined iron, stabilization of grain boundaries by segregation is effective to achieve extra hardening, as attempted by Borchers et al [155]. Taken altogether, to have extra hardening in nanocrystalline materials, grain refinement should be accompanied by other strategies such as the modification of the nature of grain boundaries and the stabilization of the microstructure by segregation or precipitates [54,55,164]. Thus, the grain size alone is not the determining factor for strengthening, but the features of grain boundaries and grains should be considered to achieve ultrahigh strength.…”

Section: Discussionmentioning

confidence: 99%

Breaks in the Hall–Petch Relationship after Severe Plastic Deformation of Magnesium, Aluminum, Copper, and Iron

et al. 2023

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Strengthening by grain refinement via the Hall–Petch mechanism and softening by nanograin formation via the inverse Hall–Petch mechanism have been the subject of argument for decades, particularly for ultrafine-grained materials. In this study, the Hall–Petch relationship is examined for ultrafine-grained magnesium, aluminum, copper, and iron produced by severe plastic deformation in the literature. Magnesium, aluminum, copper, and their alloys follow the Hall–Petch relationship with a low slope, but an up-break appears when the grain sizes are reduced below 500–1000 nm. This extra strengthening, which is mainly due to the enhanced contribution of dislocations, is followed by a down-break for grain sizes smaller than 70–150 nm due to the diminution of the dislocation contribution and an enhancement of thermally-activated phenomena. For pure iron with a lower dislocation mobility, the Hall–Petch breaks are not evident, but the strength at the nanometer grain size range is lower than the expected Hall–Petch trend in the submicrometer range. The strength of nanograined iron can be increased to the expected trend by stabilizing grain boundaries via impurity atoms. Detailed analyses of the data confirm that grain refinement to the nanometer level is not necessarily a solution to achieve extra strengthening, but other strategies such as microstructural stabilization by segregation or precipitation are required.

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Section: Discussionmentioning

confidence: 99%

Breaks in the Hall–Petch Relationship after Severe Plastic Deformation of Magnesium, Aluminum, Copper, and Iron

et al. 2023

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“…The stress-strain relationship in different metallic materials is investigated in various ways through stress and strain monitoring by developing different mathematical models [13,14], numerical analysis [15,16] and using different methods, such as thermography and digital image correlation (DIC) [17]. In this way it is possible to monitor and identify different phenomena such as inhomogeneous deformations [18] especially Lüders bands and the Portevin-Le Chatelier effect (PLC) [19].…”

Section: Introductionmentioning

confidence: 99%

The Deformation Behavior of Niobium Microalloyed Steel during Lüders Band Formation

Brlić,

Rodič,

Samardžić

et al. 2023

Metals

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In microalloyed steels, plastic instabilities often appear which have been found to be associated with changes in the microstructure. In this paper, research was carried out on the influence of the microstructure in different areas of the deformation zone during the formation of Lüders bands in niobium microalloyed steel. Thermography and digital image correlation during static tensile testing were used to research deformation behavior and the area before and during the formation of the Lüders band. Different local values of temperature changes, i.e., stress changes, and strains in the examined areas during the formation of the Lüders band were determined. The highest values of the temperature changes and strains during the formation of the Lüders band were measured in the area of the initial appearance of the Lüders band. In order to clarify the observed changes, a microstructural analysis, using X-ray diffraction, scanning electron and transmission electron microscopy methods, was used. It was established that the observed temperature, i.e., stress, and strain changes are related to changes in the microstructure. The analyses of changes in the microstructure, arrangement and interaction of dislocations with precipitates revealed significant changes in the movement of dislocations and their interaction with fine niobium-containing precipitates during the formation of Lüders bands. The influence of microstructural parameters on the Lüders band formation in niobium microalloyed steel has been established based on this research.

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“…The main qualitative pictures of a realistic law are: (a) approximately logarithmic increase of the static friction force as a function of contact timethe property, found already by Coulomb, and (b) a logarithmic dependence of the sliding friction on the sliding velocity. Both properties can be described in the frame of "state dependent" friction laws by introducing additional internal variables describing the state of the contact [17,[41][42][43] as well as shear band propagation effect on the deformation and fracture [44,45], generation and propagation of slow deformation in geomedia [46][47][48].…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Dynamics of Block Media by Movable Lattice and Movable Automata Methods

Filippov,

Popov

2023

FU Mech Eng

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Two versions of modified Burridge-Knopoff model including state dependent friction, elastic force and thermal conductivity are derived. The friction model describes a velocity weakening of friction and elasticity between moving blocks and an increase of both static friction and rigidity during stick periods as well their weakening during motion. It provides a simplified but qualitatively correct behavior including the transition from smooth sliding to stick-slip behavior, which is often observed in various tribological and tectonic systems. Attractor properties of the model dynamics is studied also. The alternative versions of the model are proposed which apply a simulation of the motion of interacting elastically connected mesh elements and motion of relatively large solid blocks, utilizing technique of the movable cellular automata. First version of the model was already basically studied before. Its advanced version here involves all components of the real system: state-depending friction and changeable rigidity, as well as heat production and thermal conductivity. Model based on the movable automata also involves the components included into traditional lattice model. It has its own ad-vantages and disadvantages which are also discussed in the paper.

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Mesoscale Deformation-Induced Surface Phenomena in Loaded Polycrystals

Cited by 5 publications

References 32 publications

Breaks in the Hall–Petch Relationship after Severe Plastic Deformation of Magnesium, Aluminum, Copper, and Iron

Breaks in the Hall–Petch Relationship after Severe Plastic Deformation of Magnesium, Aluminum, Copper, and Iron

The Deformation Behavior of Niobium Microalloyed Steel during Lüders Band Formation

Numerical Simulation of Dynamics of Block Media by Movable Lattice and Movable Automata Methods

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