On the origin of microstructural discontinuities in sliding contacts: A discrete dislocation plasticity analysis

Xu, Yingjie; Ruebeling, Friederike; Balint, D.; Greiner, Christian; Dini, Daniele

doi:10.1016/j.ijplas.2021.102942

Cited by 26 publications

(15 citation statements)

References 63 publications

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“… 38 , 39 It stands to reason that such a process is more dominant for higher normal loads. The strong dislocation activity, which we believe is responsible for the formation of new grains between the DTL and the surface of the specimen, is also confirmed in our discrete dislocation plasticity studies 25 when the larger loads are studied (see, e.g., Figure 11 of ref ( 25 )).…”

Section: Discussionsupporting

confidence: 79%

“…This is confirmed by the more detailed deterministic picture obtained using discrete dislocation plasticity in our companion paper. 25 In contrast, the microstructures for higher normal loads in Figures 1e and 2c reveal the formation of subgrains within the area between the sample surface and the DTL. For these microstructures, a piling up of dislocations moving up from the bulk is difficult to imagine.…”

Section: Discussionmentioning

confidence: 82%

“…Modeling plasticity will allow us to better understand the origin of these features. This is performed in a companion paper by Xu et al 25 These simulations reveal and explain the origin of the DTL using a discrete dislocation plasticity model. This is directly related to the formation of dislocation bands and the development of highly localized plasticity underneath the contact, manifesting as a thin band nearly parallel to the surface.…”

Section: Discussionmentioning

confidence: 95%

“…The results are expected to guide future experimental and modeling research into the initiation of microstructural discontinuities in metals under a tribological load. In this context, our companion paper 25 employed a discrete dislocation plasticity framework to simulate the microstructure evolution underneath the surface and the activity of individual dislocations.…”

Section: Introductionmentioning

confidence: 99%

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Normal Load and Counter Body Size Influence the Initiation of Microstructural Discontinuities in Copper during Sliding

Ruebeling

Richter

et al. 2021

ACS Appl. Mater. Interfaces

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Near the interface of two contacting metallic bodies in relative motion, the microstructure changes. This modified microstructure leads to changes in material properties and thereby influences the tribological behavior of the entire contact. Tribological properties such as the friction coefficient and wear rate are controlled by the microstructure, while the elementary mechanisms for microstructural changes are not sufficiently understood. In this paper, the influence of the normal load and the size of the counter body on the initiation of a tribologically induced microstructure in copper after a single sliding pass is revealed. A systematic variation in the normal load and sphere diameter resulted in maximum Hertzian contact pressures between 530 MPa and 1953 MPa. Scanning electron microscopy, focused ion beam, and transmission electron microscopy were used to probe the subsurface deformation. Irrespective of the normal load and the sphere diameter, a sharp line-like feature consisting of dislocations, the so-called dislocation trace line, was identified in the subsurface area at depths between 100 nm and 400 nm. For normal loads below 6.75 N, dislocation features are formed below this line. For higher normal loads, the microstructure evolution directly underneath the surface is mainly confined to the area between the sample surface and the dislocation trace line, which itself is located at increasing depth. Transmission Kikuchi diffraction and transmission electron microscopy demonstrate that the misorientation is predominantly concentrated at the dislocation trace line. The results disclose a material rotation around axes roughly parallel to the transverse direction. This study demonstrates the generality of the trace line phenomena over a wide range of loads and contact pressures and the complexity of subsurface processes under a sliding contact and provides the basis for modeling the early stages in the microstructure evolution.

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Section: Discussionsupporting

confidence: 79%

Section: Discussionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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Normal Load and Counter Body Size Influence the Initiation of Microstructural Discontinuities in Copper during Sliding

Ruebeling

Richter

et al. 2021

ACS Appl. Mater. Interfaces

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“…The maximum cohesive strength was set to τ max = 300 MPa and the threshold displacement jump was δ t = 0.5 nm, values we have used in our previous work [ 53 ] when we explicitly explored the origin of microstructural changes under various sliding and loading conditions. The non-softening form of the traction was adopted to help convergence of surface tractions.…”

Section: Methodsmentioning

confidence: 99%

On the Origin of Plastic Deformation and Surface Evolution in Nano-Fretting: A Discrete Dislocation Plasticity Analysis

Balint

Dini

2021

Materials

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Discrete dislocation plasticity (DDP) calculations were carried out to investigate a single-crystal response when subjected to nano-fretting loading conditions in its interaction with a rigid sinusoidal asperity. The effects of the contact size and preceding indentation on the surface stress and profile evolution due to nano-fretting were extensively investigated, with the aim to unravel the deformation mechanisms governing the response of materials subjected to nano-motion. The mechanistic drivers for the material’s permanent deformations and surface modifications were shown to be the dislocations’ collective motion and piling up underneath the contact. The analysis of surface and subsurface stresses and the profile evolution during sliding provides useful insight into damage and failure mechanisms of crystalline materials subject to nano-fretting; this can lead to improved strategies for the optimisation of material properties for better surface resistance under micro- and nano-scale contacts.

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On the origin of plasticity-induced microstructure change under sliding contacts

Balint

Greiner

et al. 2022

Friction

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Discrete dislocation plasticity (DDP) calculations are carried out to investigate the response of a single crystal contacted by a rigid sinusoidal asperity under sliding loading conditions to look for causes of microstructure change in the dislocation structure. The mechanistic driver is identified as the development of lattice rotations and stored energy in the subsurface, which can be quantitatively correlated to recent tribological experimental observations. Maps of surface slip initiation and substrate permanent deformation obtained from DDP calculations for varying contact size and normal load suggest ways of optimally tailoring the interface and microstructural material properties for various frictional loads.

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On the origin of microstructural discontinuities in sliding contacts: A discrete dislocation plasticity analysis

Cited by 26 publications

References 63 publications

Normal Load and Counter Body Size Influence the Initiation of Microstructural Discontinuities in Copper during Sliding

Normal Load and Counter Body Size Influence the Initiation of Microstructural Discontinuities in Copper during Sliding

On the Origin of Plastic Deformation and Surface Evolution in Nano-Fretting: A Discrete Dislocation Plasticity Analysis

On the origin of plasticity-induced microstructure change under sliding contacts

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