Running-in processes affecting friction and wear

Heilmann, P.; Rigney, D.

doi:10.1016/b978-0-408-01226-3.50009-3

Cited by 19 publications

(11 citation statements)

References 17 publications

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“…It is noted that bricks accumulate strain at varying rates and fail at varying points. In our structure model, the scheme shows highly deformed layers of the wall-channel (cell), fragmented structure and the grain microstructure of substrate reached at the end of running-in process [7][8][9][10][11][12][13][14]. The wall-channel structure can be described by the so-called composite model proposed by Mughrabi [47].…”

Section: Transitions Based On the Analysis Of The Dislocation Structurementioning

confidence: 99%

“…It is known that strong plastic deformation of surface layers leads to formation of cell/vein fragmented structure in the end of the running-in process [7][8][9][10][11][12][13][14]. Since the structural parameters of asperity contact are scale-dependent, let us consider initially the length scales of the cell (wall-channel) dislocation structure.…”

Section: Transitions Based On the Analysis Of The Dislocation Structurementioning

confidence: 99%

“…It is well known that all geometrical parameters of contact as well as the structure of the surface layers vary significantly during the running-in process [7][8][9][10][11][12][13]. It was shown that the structure of surface layers under friction is close to the structure in fatigue and cyclic creep [9] As a result of dislocation multiplication, the highly deformed state of surface layers is reached at the end of the runningin process.…”

Section: Characterization Of the Steady Friction Statementioning

confidence: 99%

“…There are now several experimental results and theoretical models showing strong plastic deformation of surface layers during the running-in process [7][8][9][10][11][12][13][14]. This deformation leads to the formation of a cellular/vein or fragmented structures at the end of the running-in process.…”

Section: Introductionmentioning

confidence: 98%

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Steady friction state and contact models of asperity interaction

Rapoport

2009

Wear

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Section: Transitions Based On the Analysis Of The Dislocation Structurementioning

confidence: 99%

Section: Transitions Based On the Analysis Of The Dislocation Structurementioning

confidence: 99%

Section: Characterization Of the Steady Friction Statementioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

Steady friction state and contact models of asperity interaction

Rapoport

2009

Wear

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“…Although the subject of run-in is somewhat nebulous, there is no doubt that the most obvious changes occur on the surfaces or just under them (4). These are necessarily accompanied by significant changes in the microstructure and crystallographic texture, i.e.…”

Section: Introductionmentioning

confidence: 97%

Tribological effects of roughness and running-in on oil-lubricated line contacts

Chou

Lin

1997

Proceedings of the Institution of Mechanical Engineers, Part J:

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A gear=cam adapter was employed to study various aspects of line-contact lubrication, using oil with extreme-pressure additive at two different concentrations. The effect of run-in on the tribological performance of rollers with two different surface roughnesses was investigated in terms of friction coefficient, wear loss, oil temperature, specimen roughness and electrical resistance. The relation between roller wear loss and the time rate of electrical resistance change was established. Electrical resistance versus oil temperature underwent a dramatic change during testing, a period of rising oil temperature and relatively constant low electrical resistance abruptly becoming a period of relatively constant oil temperature and rising electrical resistance, low wear rates correlating strongly with the second period. The run-in effect on roller wear loss in smooth rollers (Ra 0:076 ìm) is opposite to that in rough rollers (Ra 0:463 ìm). The asperity height of the smooth rollers was increased by wear testing irrespective of run-in; however, run-in enhanced the increase in surface roughness. The extreme-pressure additive concentration instead of run-in was the decisive factor in electrical resistance. Friction coefficients during testing showed a strong positive relation with composite surface roughness.

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Metallurgical Aspects of Sliding Wear of fcc Materials for Medical Applications

Büscher

Fischer

2003

Materialwissenschaft Werkst

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Worn surfaces of biomedical fcc alloys X2CrNiMo18-15-3, CoCr29Mo6, X13CrMnMoN18-14-3 are generated by sliding wear in order to understand the mechanisms, which bring about small wear particles. Depending on the acting wear mechanisms the debris is produced by different sites of crack initiation and paths of crack propagation. Thus, the subsurface deformation mechanisms are investigated as well. This investigation revealed that the worn surfaces of all three materials consist of a nanocrystalline layer underneath which appearances of cyclic deformation are visible. With respect to the stacking fault energy X13CrMnMoN18-14-3 as well as the CoCr29Mo6 depict sliding bands, stacking faults, and strain induced e-martensite bringing about a sufficient support of the nanocrystalline layer. Thus, 80 to 500 nm fine globular and lamellar wear particles are just torn off this layer. In contrast to this, X2CrNiMo18-15-3 shows cell walls in distances of about 50 lm below the worn surfaces, which act as sites for crack initiation and propagation. The mean wear particles are about an order of magnitude bigger and range from 20 to 250 lm. Due to the fact that the nanocrystalline layer is not supported by the material underneath it has no distinct positive effect on the wear rate.Key words: sliding wear, wear mechanisms, austenitic steels, Cobase alloys, wear particlesIn der vorliegenden Untersuchung wurden die Verschleißmecha-nismen sowie die Mechanismen zur Entstehung von Verschleißpar-tikeln kubischflächenzentrierter Legierungen untersucht. Für die Metalle X2CrNiMo18-15-3, X13CrMnMoN18-14-3 und CoCr29-Mo6 konnten mittels Transmissionselektronenmikroskopie verschiedene Schädigungsmechanismen unterhalb der verschlissenen Oberfläche beobachtet werden. Durch die plastische Verformung im artgleichen Gleitverschleiß bildet sich in den untersuchten Werkstoffen an der Oberfläche eine nanokristalline Randschicht mit einer Dicke von 2 -5 lm aus. Ein Netzwerk aus Stapelfehlern und hexagonalem Martensit unterhalb der Oberfläche des hochstickstofflegierten Stahles und der Kobaltbasislegierung bewirkt eine Verfestigung des Grundgefüges und führt somit zu einer Stabilisierung der nanokristallinen Randschicht. Der schwächste Punkt und somit der Ort der Risseinleitung befindet sich folglich unmittelbar unter der Oberfläche. Die entstandenen Partikel entsprechen in Form und Größe einzelnen bzw. Agglomeraten von nanoskopischen Körnern und sind für den hochstickstofflegierten Stahl und die Kobaltbasislegierung zwischen 80 und 500 nm. Durch die höhere Stapelfehlerenergie und die damit verbundene Möglich-keit zum Klettern und Quergleitenden der Versetzungen bilden sich in dem Grundgefüge des Stahles X2CrNiMo18-15-3 Versetzungszellen, an denen Risseinleitung und -fortschritt stattfindet. Durch diese Schwächung des Grundgefüges ist eine Stabilisierung der nanokristallinen Randschicht nicht gewährleistet und es kommt zu der Bildung von Partikeln in einer Größenordnung von 20 bis 250 lm.

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Running-in processes affecting friction and wear

Cited by 19 publications

References 17 publications

Steady friction state and contact models of asperity interaction

Steady friction state and contact models of asperity interaction

Tribological effects of roughness and running-in on oil-lubricated line contacts

Metallurgical Aspects of Sliding Wear of fcc Materials for Medical Applications

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