Login (DCU Staff Only)
Login (DCU Staff Only)

DORAS | DCU Research Repository

Explore open access research and scholarly works from DCU

Advanced Search

Laser processing of metallic surfaces for controlled micro-texturing and metallic bonding

Ahmed Obeidi, Muhannad Yasseen orcid logoORCID: 0000-0003-2733-3828 (2018) Laser processing of metallic surfaces for controlled micro-texturing and metallic bonding. PhD thesis, Dublin City University.

This study investigated the development of a novel method for designing high-end interference fit fasteners. In this work, a new surface laser treatment process was developed and implemented to enable enhanced usability and bond strength control of interference-fit connections. Stainless steel 316L cylindrical samples of 10 mm diameter were textured over a 10 mm length using a pulsed a 1.5 kW CO2 laser. The laser beam was focused one millimetre below the metal surface, with the thermal energy adjusted to bring the surface to just above the melting point to avoid the loss of the metal. Due to the localized surface melting, rotational movement of the pin and the gas jet impingement, the re-solidified metal creates raises in the sample diameter. The pin surface morphology and dimensions were precisely controlled by controlling the laser processing parameters specifically the laser beam power, the pulse repetition frequency, the rotational speed, the gas pressure, and the overlap between scan tracks. The pin was inserted into a hub hole diameter of 10.05±0.003 mm and pull out joint bond strengths were measured and examined. The results of this study showed that surface thus altered provided improved control of the bond strength, which is a particular novelty of this new interference fit joining method. Surface roughness, Ra, from 40 to 160 µm, melt pool depths from 0.4 to 1.7 mm, increases in the pin outer diameter from 0.1 to 1.1 mm, and pull out forces of up to 7.51 kN were achieved. The bond joint was found to re-grip before complete separation providing a more secure joint and increased safety. This joining method allows for the possibility of joining different materials. The modified surface layer did not reveal any distinct variation in the elastic modulus or hardness across the cross section of the insertion.
Item Type:Thesis (PhD)
Date of Award:January 2018
Supervisor(s):Brabazon, Dermot
Subjects:Engineering > Materials
Engineering > Production engineering
Engineering > Mechanical engineering
Physical Sciences > Lasers
DCU Faculties and Centres:Research Institutes and Centres > Advanced Processing Technology Research Centre (APTRC)
Research Institutes and Centres > National Centre for Plasma Science and Technology (NCPST)
DCU Faculties and Schools > Faculty of Engineering and Computing > School of Mechanical and Manufacturing Engineering
Use License:This item is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 3.0 License. View License
Funders:Enterprise Ireland
ID Code:22172
Deposited On:09 Apr 2018 09:47 by Dermot Brabazon . Last Modified 25 Jun 2021 12:24

Full text available as:

[thumbnail of PhD Thesis]
PDF (PhD Thesis) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Creative Commons: Attribution-Noncommercial-No Derivative Works 3.0


Downloads per month over past year

Archive Staff Only: edit this record