Elastic and plastic deformation of surface asperities and their load-carrying mechanisms during the formation of a real contact area

Kalin, Mitjan (author), Brodnik Žugelj, Blaž (author), Lamut, Martin (author), Hamouda, Karim (author)

How the contact behaviours of steel engineering surfaces with different roughnesses (R$_a$ = 0.1, 0.6 and 1.0 µm) are affected by the asperity work-hardening and the deformation regime are described here. Large values of the plasticity index Ψ between 20 and 50 indicate that all the surfaces should undergo a full plastic deformation. However, in the loading range up to the yield stress (on a nominal contact area) the rough surfaces exhibited at least 10 % elastic deformation, while for the smooth surfaces the elastic deformation was as much as 44 %. During the loading, the work-hardening increased the hardness of the rough surfaces by up to 63 %, and that of the smooth surfaces by up to 20 %. However, the asperities were able to carry the load that resulted in as much as a 4–10-times-higher contact pressure than the (initial) bulk yield strength. The proposed contact mechanisms for such an increased asperity-load-carrying capacity depend on the surface roughness. For the rough surfaces this is due to the work-hardening, while for the smooth surfaces the dominant mechanisms enhancing the load-carrying capacity are the work-hardening combined with the hydrostatic bulk stresses.

• Language: English
• Keywords: in-situ asperity experiments, multi-asperity contacts, real contact area, work-hardening, deformation, steel, roughness
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering; NTF - Faculty of Natural Sciences and Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2023
• Number of pages: 9 str.
• Numbering: Vol. 178, pt. A, art. 108067
• PID: 20.500.12556/RUL-142638-8fc5a1ed-3f11-8b76-cd64-979081c288c2
• UDC: 539.92
• ISSN on article: 0301-679X
• DOI: 10.1016/j.triboint.2022.108067
• COBISS.SI-ID: 129711619
• Publication date in RUL: 17.11.2022

Record is a part of a journal

• Title: Tribology international
• Shortened title: Tribol. int.
• Publisher: Elsevier
• ISSN: 0301-679X
• COBISS.SI-ID: 26558976

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: in-situ eksperimenti, kontakti več vršičkov, realna kontaktna površina, utrjevanje, deformacija, jeklo, hrapavost

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0231
• Name: Tribologija