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Choudhry, J., Almqvist, A., Prakash, B. & Larsson, R. (2023). A Stress-State-Dependent Sliding Wear Model for Micro-Scale Contacts. Journal of tribology, 145(11), Article ID 111702.
Open this publication in new window or tab >>A Stress-State-Dependent Sliding Wear Model for Micro-Scale Contacts
2023 (English)In: Journal of tribology, ISSN 0742-4787, E-ISSN 1528-8897, Vol. 145, no 11, article id 111702Article in journal (Refereed) Published
Abstract [en]

Wear is a complex phenomenon taking place as two bodies in relative motion are brought into contact with each other. There are many different types of wear, for example, sliding, fretting, surface fatigue, and combinations thereof. Wear occurs over a wide range of scales, and it largely depends on the mechanical properties of the material. For instance, at the micro-scale, sliding wear is the result of material detachment that occurs due to fracture. An accurate numerical simulation of sliding wear requires a robust and efficient solver, based on a realistic fracture mechanics model that can handle large deformations. In the present work, a fully coupled thermo-mechanical and meshfree approach, based on the momentum-consistent smoothed particle Galerkin (MC-SPG) method, is adapted and employed to predict wear of colliding asperities. The MC-SPG-based approach is used to study how plastic deformation, thermal response, and wear are influenced by the variation of the vertical overlap between colliding spherical asperities. The findings demonstrate a critical overlap value where the wear mechanism transitions from plastic deformation to brittle fracture. In addition, the results reveal a linear relationship between the average temperature and the increasing overlap size, up until the critical overlap value. Beyond this critical point, the average temperature reaches a steady-state value.

Place, publisher, year, edition, pages
American Society of Mechanical Engineers (ASME), 2023
Keywords
dry friction, flash temperature, MC-SPG, particle methods, sliding, wear mechanisms, Wear model
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-102317 (URN)10.1115/1.4063082 (DOI)2-s2.0-85175354354 (Scopus ID)
Funder
Swedish Research Council, 2020-03635
Note

Validerad;2023;Nivå 2;2023-11-13 (joosat);

License fulltext: CC BY

Available from: 2023-11-06 Created: 2023-11-06 Last updated: 2023-11-13Bibliographically approved
Tamayo, J. G., Björling, M., Shi, Y., Prakash, B. & Larsson, R. (2022). Micropitting performance of Glycerol-based lubricants under rolling-sliding contact conditions. Tribology International, 167, Article ID 107348.
Open this publication in new window or tab >>Micropitting performance of Glycerol-based lubricants under rolling-sliding contact conditions
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2022 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 167, article id 107348Article in journal (Refereed) Published
Abstract [en]

There is a high demand for environmentally friendly lubricants in order to support a transition to sustainable transport and manufacturing since conventional mineral oils derived from fossil sources are inherently harmful for the environment. Glycerol aqueous solutions have the potential to be used as environmentally friendly base fluids, due to their high solubility in water, and non-toxicity. In this investigation a micropitting test rig (MPR), was used to study the friction, wear and micropitting behaviour of Glycerol-based lubricants in a rolling/sliding contact. Micropitting and wear profiles were analysed through optical profilometry, and the morphology and evolution of micropits were studied trough scanning electron microscopy (SEM). The results showed that the steel-steel contact lubricated with a Glycerol-water-glycol lubricant reduced mild-wear, promoting micro-pitting as a main failure mode at low sliding levels compared to a commercial fully formulated gear oil. It was also shown that friction was significantly lower for the Glycerol-water and Glycerol-water-glycol lubricants which is mainly attributed to an effect of a low pressure-viscosity coefficient.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Micropitting, Green lubricant, Glycerol, Rolling-sliding
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-88181 (URN)10.1016/j.triboint.2021.107348 (DOI)000733292100004 ()2-s2.0-85120874440 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-01-01 (beamah)

Available from: 2021-12-03 Created: 2021-12-03 Last updated: 2023-09-05Bibliographically approved
Torres, H., Caykara, T., Hardell, J., Nurminen, J., Prakash, B. & Ripoll, M. R. (2022). Tribological performance of iron- and nickel-base self-lubricating claddings containing metal sulfides at high temperature. Friction, 10(12), 2069-2085
Open this publication in new window or tab >>Tribological performance of iron- and nickel-base self-lubricating claddings containing metal sulfides at high temperature
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2022 (English)In: Friction, ISSN 2223-7690, E-ISSN 2223-7704, Vol. 10, no 12, p. 2069-2085Article in journal (Refereed) Published
Abstract [en]

Iron-based coatings with the incorporation of solid lubricants have been prepared by means of laser cladding, in an effort to control friction and decrease tool wear at high temperatures during metal forming applications. The choice of a Fe-based powder has been considered advantageous, as it can lead to decreased costs compared to nickel-based claddings previously studied by the authors, in addition to having a lower environmental impact. In particular, the incorporation of transition metal dichalcogenides such as MoS2 as precursors leads to the encapsulation of silver in Fe-based self-lubricating claddings, resulting in a uniform distribution of the soft metal across the thickness of the coating. Subsequent tribological evaluation of the claddings at high temperatures shows that the addition of lubricious compounds leads to lower friction at room temperature and significantly decreased wear up to 600 °C compared to the unmodified iron-based reference alloy, although higher than similar self-lubricating Ni-based claddings. In order to cast light into these observed differences, the corresponding microstructures, phase composition, and self-lubricating mechanisms have been studied and compared for Fe- and Ni-based claddings having both of them the addition of silver and MoS2. The results suggest a key role of the formation of protective tribolayers on the counter body during high temperature sliding contact. Additional simulation of the phase evolution during solidification reveals that the formation of different chromium- and nickel-based metal sulfides in Fe- and Ni-claddings during laser cladding by the decomposition of MoS2 plays a key role in determining their tribological behaviour at high temperatures.

Place, publisher, year, edition, pages
Springer, 2022
Keywords
high temperature, laser cladding, self-lubrication, metal forming, chromium sulphide, MoS
National Category
Manufacturing, Surface and Joining Technology
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-90691 (URN)10.1007/s40544-021-0578-1 (DOI)000794092700002 ()2-s2.0-85129804095 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-11-28 (joosat);

Funder: Austrian COMET Programme (Project K2 InTribology, grant no. 872176); M-ERA.NET (project no. 872381 HOTselflub)

Available from: 2022-05-24 Created: 2022-05-24 Last updated: 2022-11-28Bibliographically approved
Decrozant-Triquenaux, J., Pelcastre, L., Courbon, C., Prakash, B. & Hardell, J. (2021). Effect of Surface Engineered Tool Steel and Lubrication on Aluminium Transfer at High Temperature. Paper presented at 23rd International Conference on Wear of Materials, Online, 26-29 April, 2021. Wear, 477, Article ID 203879.
Open this publication in new window or tab >>Effect of Surface Engineered Tool Steel and Lubrication on Aluminium Transfer at High Temperature
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2021 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 477, article id 203879Article in journal (Refereed) Published
Abstract [en]

Hot stamping is characterised by severe contact conditions, especially when forming aluminium components. In order to improve the tool lifetime, process economy, and component quality, understanding the initiation mechanisms behind aluminium transfer onto the tool surface at high temperatures is critical. To date, the tribological interaction between tools and aluminium sheets at high temperature has received limited attention. Lubricants, combined with surface engineering techniques (e.g. coatings, nitriding and surface topography control), show great potential for reducing the severity of material transfer at high temperatures. However, there is still, limited knowledge about their interaction and performance in this tribological context. In this study, high temperature tribological tests were carried out to characterise the synergetic effects of surface coatings/treatments with and without lubrication on friction and wear. A commercially available lubricant was evaluated when used in combination with uncoated, nitrided and CrWN- or DLC ta-C-based PVD coated tool steel. The tests were carried out on a hot strip drawing tribometer, employing an open contact configuration representative of the hot stamping contact conditions at two different temperatures. The counter-material was a 6082 aluminium alloy, heated up following a thermal cycle relevant for the hot stamping process. The results showed that the tribological response was highly dependent on the retention of the lubricant in the contact and the type of surface modification technique. The results show that bonding of the lubricant to the tool surface is critical. In the case of lubricant failure, severe adhesive wear and aluminium transfer onto the tool surface occurred, correlated with an increase in friction. The use of different surface engineering methods led to different results: lower friction levels could be reached when combining use of lubricant and PVD coatings compared to using uncoated or plasma nitrided tool steel. In this study, the best combination to minimise aluminium transfer and friction is the association of the lubricant with CrWN PVD coating in this study.

Place, publisher, year, edition, pages
Elsevier, 2021
Keywords
hot stamping, aluminium, lubrication, PVD coating
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-83720 (URN)10.1016/j.wear.2021.203879 (DOI)000681184400002 ()2-s2.0-85104145312 (Scopus ID)
Conference
23rd International Conference on Wear of Materials, Online, 26-29 April, 2021
Funder
Vinnova, 2017-05229
Note

Godkänd;2021;Nivå 0;2021-08-11 (alebob);Konferensartikel i tidskrift

Available from: 2021-04-16 Created: 2021-04-16 Last updated: 2021-08-16Bibliographically approved
Decrozant-Triquenaux, J., Pelcastre, L., Courbon, C., Prakash, B. & Hardell, J. (2021). High temperature tribological behaviour of PVD coated tool steel and aluminium under dry and lubricated conditions. Friction, 9(4), 802-821
Open this publication in new window or tab >>High temperature tribological behaviour of PVD coated tool steel and aluminium under dry and lubricated conditions
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2021 (English)In: Friction, ISSN 2223-7690, E-ISSN 2223-7704, Vol. 9, no 4, p. 802-821Article in journal (Refereed) Published
Abstract [en]

Aluminium alloys are commonly used as lightweight materials in the automotive industry. This non-ferrous family of metallic alloys offers a high versatility of properties and designs. To reduce weight and improve safety, high strength-to-weight ratio alloys (e.g. 6XXX and 7XXX), are increasingly implemented in vehicles. However, these alloys exhibit low formability and experience considerable springback during cold forming, and are therefore hot formed. During forming, severe adhesion (i.e. galling) of aluminium onto the die surface takes place. This phenomenon has a detrimental effect on the surface properties, geometrical tolerances of the formed parts and maintenance of the dies. The effect of surface engineering as well as lubricant chemistry on galling has not been sufficiently investigated. Diamond-like carbon (DLC) and CrN physical vapour deposition (PVD) coated steel have been studied to reduce aluminium transfer. However, the interaction between lubricants and PVD coatings during hot forming of aluminium alloys is not yet fully understood. The present study thus aims to characterise the high temperature tribological behaviour of selected PVD coatings and lubricants during sliding against aluminium alloy. The objectives are to first select promising lubricant-coating combinations and then to study their tribological response in a high-temperature reciprocating friction and wear tester. Dry and lubricated tests were carried out at 300 °C using a commercial polymer lubricant. Tests using DLC, CrN, CrTiN, and CrAlN coated tool steel were compared to uncoated tool steel reference tests. The initial and worn test specimen surfaces were analysed with a 3-dimensional (3D) optical profiler, scanning electron microscope (SEM) and energy dispersive X-ray spectroscope (EDS) as to understand the wear mechanisms. The results showed formation of tribolayers in the contact zone, reducing both friction and wear. The stability of these layers highly depends on both the coatings’ roughness and chemical affinity towards aluminium. The DLC and CrN coatings combined with the polymer lubricant were the most effective in reducing aluminium transfer.

Place, publisher, year, edition, pages
Springer, 2021
Keywords
high temperature tribology, aluminium, lubrication, physical vapour deposition (PVD) coatings, material transfer, adhesion
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-81956 (URN)10.1007/s40544-020-0435-7 (DOI)000595394000005 ()2-s2.0-85097031328 (Scopus ID)
Funder
Vinnova, 2015-01352
Note

Validerad;2021;Nivå 2;2021-04-13 (alebob);

Finansiär: RISE

Available from: 2020-12-11 Created: 2020-12-11 Last updated: 2021-04-13Bibliographically approved
Pelcastre, L., Kurnia, E., Hardell, J., Decrozant-Triquenaux, J. & Prakash, B. (2021). High temperature tribological studies on hardfaced tool steels for press hardening of Al-Si coated boron steel. Wear, 476, Article ID 203728.
Open this publication in new window or tab >>High temperature tribological studies on hardfaced tool steels for press hardening of Al-Si coated boron steel
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2021 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 476, article id 203728Article in journal (Refereed) Published
Abstract [en]

Press hardening tools are expected to operate satisfactorily for thousands of forming cycles before being replaced. An approach to enhance the durability of tools in operation, and improve the process economy, is to refurbish them by depositing new material on the tool through welding, or hardfacing, when its surface is adversely damaged. The welding process changes the microstructure of the original tool steel and the deposited material also has a different microstructure, as well as different chemical composition to facilitate the welding process. Dissimilar friction behaviour between the original tool steel and the welded material can lead to unstable friction forces during forming. This work therefore focuses on understanding the tribological behaviour of different hardfacing materials, deposited through TIG welding, and their interaction with Al-Si coated boron steel at high temperatures. The tribological behaviour is evaluated using a hot-strip drawing tribometer capable of simulating the sliding conditions in the press hardening process. The effect of temperature on the microstructure and on the friction and wear behaviour of the weld material is also studied by conducting tests at room temperature and at 500°C. In general, friction and the governing wear mechanisms are similar for the evaluated hardfacing materials. Friction stability was observed to be closely related to the temperature of the workpiece material. Temperature of the tool significantly affects the formation and structure of material transfer layers onto tool steels.

Place, publisher, year, edition, pages
Elsevier, 2021
Keywords
High temperature tribology, repaired tools, press hardening, hardfacings
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-83090 (URN)10.1016/j.wear.2021.203728 (DOI)000679095200001 ()2-s2.0-85102111633 (Scopus ID)
Funder
Vinnova, 2017-05229
Note

Validerad;2021;Nivå 2;2021-08-06 (beamah)

Available from: 2021-02-26 Created: 2021-02-26 Last updated: 2021-08-06Bibliographically approved
Moghaddam, P. V., Prakash, B., Vuorinen, E., Fallqvist, M., Andersson, J. M. & Hardell, J. (2021). High temperature tribology of TiAlN PVD coating sliding against 316L stainless steel and carbide-free bainitic steel. Tribology International, 159, Article ID 106847.
Open this publication in new window or tab >>High temperature tribology of TiAlN PVD coating sliding against 316L stainless steel and carbide-free bainitic steel
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2021 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 159, article id 106847Article in journal (Refereed) Published
Abstract [en]

Reciprocating sliding wear tests were performed on TiAlN coating against 316L stainless steel and carbide-free bainitic steel at temperatures of 40, 400 and 800 oC. The results indicate that material transfer is more pronounced for the softer stainless steel at lower temperatures but at 800 oC, carbide-free bainite exhibits relatively more material transfer. Friction coefficient of stainless steel increases when temperature increases. However, for carbide-free bainite, there is a reduction in friction coefficient at elevated temperatures. This can be attributed to formation of an easily sheared iron oxide layer at elevated temperatures. In case of stainless steel, generation of a thin tribofilm containing aluminium oxide and oxidised transferred material can protect the TiAlN coating against wear at 800 oC.

Place, publisher, year, edition, pages
Elsevier, 2021
Keywords
tribology, high temperature, PVD coating, stainless steel
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear) Other Materials Engineering
Research subject
Machine Elements; Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-82245 (URN)10.1016/j.triboint.2020.106847 (DOI)000639769600001 ()2-s2.0-85101922273 (Scopus ID)
Funder
Vinnova, 2017-02915
Note

Validerad;2021;Nivå 2;2021-03-15 (johcin)

Available from: 2021-01-11 Created: 2021-01-11 Last updated: 2022-11-02Bibliographically approved
Decrozant-Triquenaux, J., Pelcastre, L., Prakash, B. & Hardell, J. (2021). Influence of Lubrication, Tool Steel Composition and Topography on the High Temperature Tribological Behaviour of Aluminium. Friction, 9(1), 155-168
Open this publication in new window or tab >>Influence of Lubrication, Tool Steel Composition and Topography on the High Temperature Tribological Behaviour of Aluminium
2021 (English)In: Friction, ISSN 2223-7690, E-ISSN 2223-7704, Vol. 9, no 1, p. 155-168Article in journal (Refereed) Published
Abstract [en]

The use of high strength aluminium alloys, such as 6XXX and 7XXX series, is continuously increasing for automotive applications in view of their good strength-to-weight ratio. Their formability at room temperature is limited and they are thus often formed at high temperatures to enable production of complex geometries. Critical challenges during hot forming of aluminium are the occurrence of severe adhesion and material transfer onto the forming tools. This negatively affects the tool life and the quality of the produced parts. In general, the main mechanisms involved in the occurrence of material transfer of aluminium alloys at high temperature are still not clearly understood. Therefore, this study is focussed on understanding of the friction and wear behaviour during interaction of Al6016 alloy and three different tool steels in as-received and polished state. The tribotests were carried out under dry and lubricated conditions, with two distinct lubricants, using a reciprocating friction and wear tester. The worn surfaces were analysed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results showed a high dependence of friction and wear behaviour on the tool steel roughness as well as on the stability of the lubricant films. Tribolayers were found to develop in the contact zone and their capacity to improve the tribological behaviour is seen to be drastically impacted by the surface roughness of the tool steel. When the tribolayers failed, severe adhesion took place and led to high and unstable friction as well as material transfer to the tool steel.

Place, publisher, year, edition, pages
Springer, 2021
Keywords
friction, wear, high temperature tribology, aluminium, lubrication, tribolayer
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-77692 (URN)10.1007/s40544-020-0371-6 (DOI)000565156500001 ()2-s2.0-85090143600 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-10-08 (alebob)

Available from: 2020-02-13 Created: 2020-02-13 Last updated: 2020-12-16Bibliographically approved
Meng, Y., Xu, J., Jin, Z., Prakash, B. & Hu, Y. (2020). A review of recent advances in tribology. Friction, 8, 221-300
Open this publication in new window or tab >>A review of recent advances in tribology
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2020 (English)In: Friction, ISSN 2223-7690, E-ISSN 2223-7704, Vol. 8, p. 221-300Article, review/survey (Refereed) Published
Abstract [en]

The reach of tribology has expanded in diverse fields and tribology related research activities have seen immense growth during the last decade. This review takes stock of the recent advances in research pertaining to different aspects of tribology within the last 2 to 3 years. Different aspects of tribology that have been reviewed including lubrication, wear and surface engineering, biotribology, high temperature tribology, and computational tribology. This review attempts to highlight recent research and also presents future outlook pertaining to these aspects. It may however be noted that there are limitations of this review. One of the most important of these is that tribology being a highly multidisciplinary field, the research results are widely spread across various disciplines and there can be omissions because of this. Secondly, the topics dealt with in the field of tribology include only some of the salient topics (such as lubrication, wear, surface engineering, biotribology, high temperature tribology, and computational tribology) but there are many more aspects of tribology that have not been covered in this review. Despite these limitations it is hoped that such a review will bring the most recent salient research in focus and will be beneficial for the growing community of tribology researchers.

Place, publisher, year, edition, pages
Springer, 2020
Keywords
tribology, biotribology, lubrication, superlubricity, friction, wear, surface engineering
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:ltu:diva-80920 (URN)10.1007/s40544-020-0367-2 (DOI)000523031600001 ()2-s2.0-85083230966 (Scopus ID)
Available from: 2020-09-24 Created: 2020-09-24 Last updated: 2023-09-14Bibliographically approved
Hultqvist, T., Shirzadegan, M., Vrček, A., Baubet, Y., Prakash, B., Marklund, P. & Larsson, R. (2020). Corrigendum to “Elastohydrodynamic lubrication for the finite line contact under transient loading conditions” [Tribol Int 127 (2018) 489–499]. Tribology International, 150, Article ID 106414.
Open this publication in new window or tab >>Corrigendum to “Elastohydrodynamic lubrication for the finite line contact under transient loading conditions” [Tribol Int 127 (2018) 489–499]
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2020 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 150, article id 106414Article in journal (Other academic) Published
Place, publisher, year, edition, pages
Elsevier, 2020
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-79986 (URN)10.1016/j.triboint.2020.106414 (DOI)000539161200040 ()2-s2.0-85084483564 (Scopus ID)
Note

Godkänd;2020;Nivå 0;2020-06-24 (alebob);

Erratum in: Tribology International, vol. 127, p. 489–499, DOI: 10.1016/j.triboint.2020.106414

Available from: 2020-06-24 Created: 2020-06-24 Last updated: 2023-09-05Bibliographically approved
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