Laser-based surface treatment of CFRP and aluminum for adhesively bonded hybrid joints

Jochen Schanz, Michael Gooßen, Dieter Meinhard, David Harrison, Anjali De Silva, Volker Knoblauch, Harald Riegel

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


Carbon fiber reinforced polymer (CFRP) offers the highest potential for lightweight applications due to its excellent weight to strength ratio in comparison to other materials. However, it is cost-intensive and therefore rarely used monolithically. This makes pretreatment and joining processes so important. Hybrid connections of CFRP and metals can be made by riveting, bolting, stir joining and by adhesive. For adhesive bonding, a pretreatment of the materials is necessary. A laser pretreatment has the advantage, that it is automatable and contactless. This paper deals with the pretreatment of CFRP with different laser wavelengths in near-infrared (NIR, 1030 and 1064 nm) and ultraviolet (UV, 355 nm) range. The influence of the processing direction relative to the fiber layer and the influence of the energy density was investigated with a short pulsed NIR infrared laser. In addition, the influence of different surface structures on the mechanical strength was investigated. The treated CFRP surfaces were examined with a light microscope and a scanning electron microscope. The tensile shear strengths were determined using CFRP and aluminum substrates, joined with a 2-part epoxy adhesive. As a comparison, UV laser treated specimens were also mechanically tested. An ultra-short pulsed NIR laser system was used to generate periodic structures on the CFRP to maximize the surface area without fiber damage and breakage. The investigations on the influence of the machining direction with NIR relative to the fiber layer showed insignificant differences in shear strengths. The variation of the energy density showed an influence on the ablation behavior of the CFRP matrix and the mechanical strength. The maximum strength with a cohesive failure in the adhesive was achieved with optimized short pulsed NIR laser parameter.

Original languageEnglish
Title of host publicationLaser-Based Micro- and Nanoprocessing XIV
EditorsUdo Klotzbach, Akira Watanabe, Rainer Kling
Number of pages11
ISBN (Electronic)9781510632998
Publication statusPublished - 9 Mar 2020
EventLaser-Based Micro- and Nanoprocessing XIV - San Francisco, United States
Duration: 3 Feb 20206 Feb 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceLaser-Based Micro- and Nanoprocessing XIV
Country/TerritoryUnited States
CitySan Francisco


  • Adhesive bonding
  • Aluminum
  • Carbon fiber reinforced polymer
  • Hybrid material joint
  • Laser pretreatment
  • Near infrared
  • Short pulsed
  • Ultra-short pulsed
  • Ultraviolet

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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