Adhesion suppresses atomic wear in single-asperity sliding

Yang, Yongjian; Huang, Liping; Shi, Yunfeng

doi:10.1016/j.wear.2016.02.002

Cited by 42 publications

(46 citation statements)

References 37 publications

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“…The magnitude of critical stress σ ⁎ 0 separating the regions of two different mechanisms of asperity interaction depends on the values σ j and a as well as on other material parameters (among them are yield stress, strain hardening coefficient, and Young's modulus). These findings qualitatively well correlate with the results of molecular dynamics analysis of wear modes of nanoscopic asperities 11 . A clear boundary between atomic wear at low values of the work of adhesion (this can be considered as an analog of above-shown slipping mode) and much more intensive plastic wear at high values of the work of adhesion (analog of grinding-based mode) is theoretically shown in this paper.…”

Section: Numerical Analysis Of the Regimes Of Wearsupporting

confidence: 86%

“…Interacting asperities had equal size and trapezoidal shape -one of the typical simplified shapes used for generic studies of properties of "asperities" (see e.g. 11 ). The height of asperity was about D = 0.5 mm (500 μm), the size of a discrete element was d = 0.025 mm (25 μm).…”

Section: Problem Statementmentioning

confidence: 99%

“…For separation, the Drucker-Prager condition was used (see Eq. (11) in the "Methods" section). This condition contains parameter a, which governs the brittleness of the material: it equals to 1 for highly ductile metals and polymers, while reaches 5-10 for elastic-brittle solids.…”

Section: Problem Statementmentioning

confidence: 99%

“…Introduction of rebonding results in the relative sliding consisting of a sequence of local bonding/debonding acts in the contact patches. Strength of newly bonded patches is characterized by pure shear strength and shear strength sensitivity to local pressure (the parameters σ j and a respectively in fracture criterion (11)). (2) The presence of attractive normal interaction between spatially separated surfaces ("broken" or potential new contact patches).…”

Section: Numerical Analysis Of the Regimes Of Wearmentioning

confidence: 99%

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Role of Adhesion Stress in Controlling Transition between Plastic, Grinding and Breakaway Regimes of Adhesive Wear

Dimaki

Shilko

Dudkin

et al. 2020

Sci Rep

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A discrete-element based model of elastic-plastic materials with non-ideal plasticity and with an account of both cohesive and adhesive interactions inside the material is developed and verified. Based on this model, a detailed study of factors controlling the modes of adhesive wear is performed. Depending on the material and loading parameters, we observed three main modes of wear: slipping, plastic grinding, cleavage, and breakaway. We find that occurrence of a particular mode is determined by the combination of two dimensionless material parameters: (1) the ratio of the adhesive stress to the pure shear strength of the material, and (2) sensitivity parameter of material shear strength to local pressure. the case study map of asperity wear modes in the space of these parameters has been constructed. Results of this study further develop the findings of the widely discussed studies by the groups of J.-f. Molinari and L. pastewka.Adhesive wear is a complex, multiscale and still poorly understood phenomenon 1-3 . This kind of wear occurs in contact pairs where materials of interacting bodies are characterized by equal or similar values of hardness with the possible transfer of material from one surface to the opposite one. Since the publication of Rabinowicz from 1958 4 , it is known that adhesive wear is controlled by the relation of material parameters including elastic modulus, hardness and specific surface energy 4,5 . In a series of recent works by Aghababaei, Molinari et al., it was shown that adhesive wear may develop in two ways: 1) formation and evolution (growth or fragmentation) of wear particles or 2) plastic deformation of micro contacts accompanied by smoothing of asperities 6,7 . These studies together with works by other research groups 8-11 created a solid basis for a theoretical understanding of wear modes and opened possibilities for a new interpretation of classical concepts. In particular, the adhesive wear mode criterion by Rabinowicz was critically revised and details were disclosed of how the wear process occurs in both regimes of debris formation and plastic smoothing.The above mentioned fundamental results revealing the features of asperity fracture and wear were obtained using pseudo molecular dynamics (MD) simulation at the mesoscale, so the question remained whether these conclusions are universal and applicable to real materials. A particular problem of meso MD models consists in the difficulty of separating the plastic and adhesive properties of material as in meso molecular dynamics both of them are determined by the same interaction potential. On the mesoscopic scale, it may be necessary, firstly, to decouple strength from adhesion parameters of the material and, secondly to take into account more complex material properties such as yield stress and strain hardening, both strongly dependent on features of internal structure at lower scales (grain structure, grain boundaries, inclusions of other phases, etc.). This substantiates the need for a detailed theoretical analysis of wear r...

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Section: Numerical Analysis Of the Regimes Of Wearsupporting

confidence: 86%

Section: Problem Statementmentioning

confidence: 99%

Section: Problem Statementmentioning

confidence: 99%

Section: Numerical Analysis Of the Regimes Of Wearmentioning

confidence: 99%

See 2 more Smart Citations

Role of Adhesion Stress in Controlling Transition between Plastic, Grinding and Breakaway Regimes of Adhesive Wear

Dimaki

Shilko

Dudkin

et al. 2020

Sci Rep

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“…The quality of AFM-based measurements and manufacturing processes are critically dependent on the reliability and durability of AFM tip itself [1][2][3][4][5]. However, the contact between the tip and sample, and the associated high mechanical stress and/or chemical reactions, can result in wear of the tip during use [6][7][8][9][10][11][12][13]. Tip wear is undesirable because it can result in an inability to resolve fine structures during AFM implementation [14].…”

Section: Introductionmentioning

confidence: 99%

Amorphization-assisted nanoscale wear during the running-in process

Altoé

Martini

2017

Wear

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Atomistic simulations were used to study the nanoscale wear of crystalline silicon with a native oxide sliding against amorphous silicon dioxide. The size, shape and crystallographic orientation of the model were defined to be comparable to those in a corresponding atomic force microscope experiment, where the tip was imaged before and after 40 nm of sliding using ex situ transmission electron microscopy. Tip wear was quantified in the simulation as the volume of silicon atoms removed from the tip at intervals up to 40 nm sliding distance. We also quantified amorphization during sliding as the change of tip material from crystalline to amorphous. The rate of amorphization decreased with sliding distance, and this trend was analyzed in the context of a previously-proposed analytical model for crystalline-to-amorphous transitions and explained qualitatively by local strain distributions within the tip. Both wear and amorphization were found to exhibit similar trends, but the wear rate was faster than the rate of amorphization. The results suggest that amorphization may be a dominant mechanism of nanoscale wear during the early stages of running-in, but less so during steady-state sliding.

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