Interactions between Dislocations and Boundaries during Deformation

Pan, Hongjiang; He, Yue; Zhang, Xiaodan

doi:10.3390/ma14041012

Cited by 78 publications

(38 citation statements)

References 180 publications

(486 reference statements)

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“…In the case of the softer Cu coatings produced from electrolyte II, the radius of the plastic zone is larger than the radius of the plastic zone in the coatings produced from electrolyte I and, then, the indentation depth is higher (see Figure 6a,b). The plastic deformation of fine-grained coatings occurs throughout the grain with the slip of dislocations mostly in the grain interior (intragranular slip) [60]. For Cu coatings whose grain size is in the order of nanometers, this mechanism is not possible.…”

Section: Discussionmentioning

confidence: 99%

Structural, Mechanical and Electrical Characteristics of Copper Coatings Obtained by Various Electrodeposition Processes

et al. 2022

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Mechanical (hardness and adhesion) and electrical (sheet resistance) characteristics of electrolytically produced copper coatings have been investigated. Morphologies of Cu coatings produced galvanostatically at two current densities from the basic sulfate electrolyte and from an electrolyte containing levelling/brightening additives without and with application of ultrasound for the electrolyte stirring were characterized by SEM and AFM techniques. Mechanical characteristics were examined by Vickers microindentation using the Chen–Gao (C–G) composite hardness model, while electrical characteristics were examined by the four-point probe method. Application of ultrasound achieved benefits on both hardness and adhesion of the Cu coatings, thereby the use of both the larger current density and additive-free electrolyte improved these mechanical characteristics. The hardness of Cu coatings calculated according to the C–G model was in the 1.1844–1.2303 GPa range for fine-grained Cu coatings obtained from the sulfate electrolyte and in the 0.8572–1.1507 GPa range for smooth Cu coatings obtained from the electrolyte with additives. Analysis of the electrical characteristics of Cu coatings after an aging period of 4 years showed differences in the sheet resistance between the top and the bottom sides of the coating, which is attributed to the formation of a thin oxide layer on the coating surface area.

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Section: Discussionmentioning

confidence: 99%

Structural, Mechanical and Electrical Characteristics of Copper Coatings Obtained by Various Electrodeposition Processes

et al. 2022

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“…To determine the mean deformation of a crystal, at any displacement x of the dislocations contained therein, consideration is taken, in the sliding plane represented in Figure 4, of the dislocation AB with the Burgers vector, b; this dislocation moves to the dotted position A'B' under the force action which causes the displacement. If an external force, F, determines the plane of sliding the tangential component of tension (the shear tension) [27,32], τ, then the tangential force acting on the unit of dislocation length is Fd and:…”

Section: The Forces That Cause Movement Of Dislocationsmentioning

confidence: 99%

“…Thus, under selective transfer conditions, the interaction between dislocations and the free surface of the superficial selective layer must be taken into account. In this case, the unitary interaction force tends to move the dislocations to the surface under the action of tangential tensions (displacement by slipping), and described by the following relation [9]: If an external force, F, determines the plane of sliding the tangential component of tension (the shear tension) [27,32], τ, then the tangential force acting on the unit of dislocation length is F d and:…”

Section: The Forces That Cause Movement Of Dislocationsmentioning

confidence: 99%

“…The relationship ( 5) is valid for the displacement of the dislocations under the action of tangential tensions (displacement by slip), and when the displacement of the dislocations happens under the action of the normal stretching or compression stresses (displacement by climb) [27,32], and F d , becomes:…”

Section: The Forces That Cause Movement Of Dislocationsmentioning

confidence: 99%

“…Any dislocation is surrounded by a tensions field that generates forces that produce the displacement of the dislocations. This field can be produced by the application of some external tensions or the existence of defects of the crystal lattice, such as dissolved foreign atoms, precipitated secondary phase particles, and other dislocations [24,26,32]. The components of this field can be determined with help by the elasticity theory, but only from a distance ρ 0 from the core of the dislocation because, in the immediate vicinity of the core of dislocation, deformation is too large to be treated with the elasticity theory (ρ 0 is the dislocation core radius).…”

Section: The Stresses/tensions Field Of a Dislocationmentioning

confidence: 99%

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A Modelling Study of the Correlation between the Layer Obtained by Selective Transfer and the Dislocations Movement at the Friction Surfaces Limit

Ilie

Ipate

2022

Metals

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The selective transfer phenomenon (STP) is based on physico-chemical processes occurring in the contact area of a friction pair, with an element from a copper alloy and allows the metallic transfer of particles of micro/nanometric size, forming a thin superficial tribologically performing layer under energy and relative motion conditions. During the formation of the layer, its crystalline network has an excess of defects and this makes the dislocations to come to the surface. The layer thickness is small, porous, and with comparable dimensions to those of the tensions field of the dislocations. This paper presents a review and analysis of the STP based on dislocations movement to establish and know the tensions field influence, the energy (about 0.25 J/m), and the linear tension of dislocations (~2.42 × 10−9 N) at the contact surfaces zone of a friction pair, by which we can ensure a low wear state (~4.16 × 10−5–2.16 × 10−4 g/min), and a reduced friction coefficient (~0.014–0.034). Therefore, the purpose of the paper is to analyze the STP based on the dislocations movement because is proves the existence (presence), importance, and utility of the dislocations, respectively, the dislocations movements during the conditions’ selective transfer, at the limit of the friction surfaces, under the action of a tensions field, whose components are determined analytically by modelling, together with energy and the linear tension. Also, the layer formed through STP has the property of ensuring during the deformation process an agglomeration of dislocations (structural defects) which protects it from destruction, and therefore, a self-regulation of the equilibrium processes, disturbed during the friction process, to maintain the friction and wear of the friction pairs within reduced limits.

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Cyclic Failure of a Cr–Au Bilayer on Polyimide: In Situ Transmission Electron Microscopy Observations of Interfacial Dislocation Mechanisms

Gebhart,

Krapf,

Schretter

et al. 2024

Adv Eng Mater

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This work presents in situ transmission electron microscopy observations of dislocation activities and associated fatigue properties in a cross‐sectional sample of a Cr–Au bilayer on a polyimide substrate under cyclic loading. Dislocation structures in the Au layer are observed to evolve into a geometrically necessary boundary parallel to the Cr–Au interface, which significantly impedes dislocation motion and plays a crucial role in enhancing the fatigue resistance of the studied sample. While a comparison to the damage in a conventional blanket film testing geometry reveals some differences in the accumulation of plastic flow, the findings can provide insights into the underlying mechanisms governing fatigue in nanostructured multilayer materials on polymer substrates.

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Interactions between Dislocations and Boundaries during Deformation

Cited by 78 publications

References 180 publications

Structural, Mechanical and Electrical Characteristics of Copper Coatings Obtained by Various Electrodeposition Processes

Structural, Mechanical and Electrical Characteristics of Copper Coatings Obtained by Various Electrodeposition Processes

A Modelling Study of the Correlation between the Layer Obtained by Selective Transfer and the Dislocations Movement at the Friction Surfaces Limit

Cyclic Failure of a Cr–Au Bilayer on Polyimide: In Situ Transmission Electron Microscopy Observations of Interfacial Dislocation Mechanisms

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