An attempt to produce ex situ TTS to understand their mechanical formation conditions – The case of an ultra high purity iron

Descartes, Sylvie; Busquet, Magali; Berthier, Yves

doi:10.1016/j.wear.2011.01.089

Cited by 28 publications

(17 citation statements)

References 27 publications

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“…Just below TBL there is "tribological transformed structure" (TTS) layer with a thickness of 5-10 μm, in which the grain boundary cannot be observed. TTS layer has been reported in many researches [17][18][19]. Just beneath the TTS layer some elongated grains, that boundaries are parallel to the fretting direction, can be found, which we call a general deformation region (GDR) with a thickness of 5-10 μm.…”

Section: Fig 1(a)mentioning

confidence: 85%

“…However, TTS layer is first time to be found in Inconel 600 alloy. It is believed that the formation of nanolisation of TTS layer can be related to the high hydrostatic stress components, high local plastic strains and high strain gradients [19], and its reason is supposed to be the formation of mechanical microtwins and subsequent interaction of the microtwins with dislocation [24], which needs to be further investigated. …”

Section: Discussionmentioning

confidence: 99%

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Effects of displacement amplitude on fretting wear behaviors and mechanism of Inconel 600 alloy

2013

Wear

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Section: Fig 1(a)mentioning

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Effects of displacement amplitude on fretting wear behaviors and mechanism of Inconel 600 alloy

2013

Wear

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“…Future work will investigate the correlation between micropillar compression curves and the representative stress-strain values obtained from nano-indentation tests [16,56]. Quantification of the mechanical property gradients presented in transformed surfaces induced by other kinds of contact loading treatment, as for high pressure torsion (HPT) [7,45] or micro-percussion tests [57, , 58] will also be addressed.…”

Section: Discussionmentioning

confidence: 99%

Assessment of mechanical property gradients after impact-based surface treatment: application to pure α-iron

Tumbajoy-Spinel

Descartes

Bergheau

et al. 2016

Materials Science and Engineering: A

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Mechanical surface treatments are known for their ability to improve material resistance to abrasive wear and local fatigue crack microstructure of the home-made crack propagation. These treatments are based on repeated contact loadings which create large plastic strains in the near-surface that can induce a local grain refinement. In this case, a significant increase in the near-surface local mechanical properties is thus usually observed. In this paper, nano-mechanical tests are used to quantify the mechanical property gradient in the near-surface of a purity-controlled α-iron after an impact-based treatment. A methodology based on the combination of two different techniques is proposed: nano-indentation and in-situ micro-pillar compression. The resulting in-depth mechanical properties gradient is compared to the average grain size measured by EBSD. A positive relationship with the well-known Hall-Petch effect is observed.

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“…It has been known for many years that, under friction stresses, specific layers with more or less "amorphous" feature are observed on the sub-surfaces of ductile materials. These layers (Tribologically Transformed Surfaces (TTS) or Superficial Tribological Transformations (STT) or Mechanically Modified Superficial (MMS) structures) are the result of changes in the microstructural features, chemical composition, and mechanical and thermal properties of the ductile friction surfaces submitted to large plastic deformations under high hydrostatic pressures, even at low temperatures [1][2][3]. Some authors [4] consider that all metallurgical transformations within TTS are linked to the modification of mechanical and physical properties and also to the heat exchanges and/or volume variations that produce expansion or shrinkage of the sub-surface, and therefore produce internal stresses according to the direction of the transformation.…”

Section: Introductionmentioning

confidence: 99%

“…As Berthier [2] has shown, the TTS are the responses permitting the production of the "Third-Body" with the minimum amount of surface degradation through friction. The terms most often used to describe a ductile tribological sub-surface are "plastic deformation (or plastic strain)", "Mechanically Modified Superficial structures", and also "cumulative plastic strain (or ratcheting)" [3,6,17]. Because these expressions imply broad physical concepts, more and more authors are investigating how to develop them in terms of physical mechanisms [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Shear mode M3 in the first sites of ductile metallic alloys: Some considerations on the physical mechanisms leading to internal particle flows

Boher

Vidal

Cabrol

et al. 2019

Wear

Self Cite

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This paper examines plastic mechanisms that lead to damage to the sub-surfaces of ductile metallic contact areas and, by extension, to the creation of wear particles. The word "damage" is used here as a generic term to designate all topological, morphological and/or microstructural modifications to the surfaces that are the consequence of interfacial shear stress under friction. During friction, the accommodation mechanisms of plastic deformation by the M3 mode in the contact area can be different, depending on the microstructures of the alloy and the first sites (bulk materials). For example, for tempered martensitic steels under frictional stresses, plasticity strain occurs in Tribologically Transformed Surfaces (TTS) under dislocation gliding. The creation of new dislocations and the rearrangement of all these dislocations into a "bamboo"-type structure leads to a decrease in hardness, or softening of the steel. Otherwise, depending on the stacking fault energy in alloy microstructures, plasticity may occur through mechanisms involving either perfect dislocation gliding and/or partial dislocation gliding. In addition to hardening, the mobility and morphology of dislocations are also related to stacking fault energy, which can promote phase transformation leading to shear strain in TTS. These shear strain mechanisms have a great influence on the internal flow of wear particles and on the formation of the "Third-body layers". These findings are given in a review of tribological results of measurements carried out on a wrought X38CrMoV5 grade steel and on cobalt-base thick coatings, using tribometers, under various loadings, test temperatures and sliding speeds. The cobalt-base thick coatings are deposited on steel by several processes which modify the nominal chemical composition of the cobalt alloy and make it possible to study the influence of the iron content on shear strain under friction stresses.

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An attempt to produce ex situ TTS to understand their mechanical formation conditions – The case of an ultra high purity iron

Cited by 28 publications

References 27 publications

Effects of displacement amplitude on fretting wear behaviors and mechanism of Inconel 600 alloy

Effects of displacement amplitude on fretting wear behaviors and mechanism of Inconel 600 alloy

Assessment of mechanical property gradients after impact-based surface treatment: application to pure α-iron

Shear mode M3 in the first sites of ductile metallic alloys: Some considerations on the physical mechanisms leading to internal particle flows

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