Laser surface treatment of CFRP composites for a better adhesive bonding owing to the mechanical interlocking mechanism

Abstract

Adhesion can be greatly improved by the correct surface preparation techniques. One of the most common and useful technique is specific surface structuring which leads to mechanical interlocking and greater adhesion. This work describes the effect of laser-induced line pattern surface structuring on the mechanical interlocking mechanism and so on the adhesive bonding of carbon fiber reinforced polymer (CFRP) composites. Surface patterns with different laser scribes were obtained by CO 2 laser treatment. The effect of the number of a laser shot, the scribe depth, the number of the scribe and the angle between the direction of the laser scribes and mechanical test direction on the adhesive bonding strength of CFRP/CFRP joints was investigated by performing the single lap shear tests according to the ASTM D5868-01. After destructive tests, damaged surfaces were analyzed for determining the failure mechanisms. Mechanical tests showed that laser scribe characteristics especially the number of laser shot and the number of scribes have significant effects on the mechanical interlocking mechanism and so on the adhesion bonding strength. It is suggested that in order to improve the adhesion strength of CFRP/CFRP joints, mechanical interlocking mechanism shall be obtained by optimized laser scribe patterns. POLYM. COMPOS., 40:3611-3622, 2019.

Co-Bonded Hybrid Thermoplastic-Thermoset Composite Interphase: Process-Microstructure-Property Correlation

“…Thermoplastic-thermoset MMCs combine the damage tolerance characteristics, and welding capability of thermoplastics with the strength and stiffness of thermoset composites resulting in more reliable structures with an extended lifetime [ 4 , 5 , 6 ]. However, joining thermoplastics to thermosets remains a challenging step despite the development of various joining technologies for composite structures including (i) mechanical fastening [ 7 , 8 , 9 ], (ii) welding [ 10 , 11 , 12 , 13 ], (iii) adhesive bonding [ 14 , 15 , 16 ], (iv) co-curing (parts are cured at the same time) [ 17 , 18 ], and (v) hybrid joints (combination of two or more of previous methods) [ 19 , 20 , 21 ]. Nevertheless, all these joining methods have disadvantages in terms of being unreliable, labour-intensive, time-consuming and expensive [ 22 ].…”

Joining processes of CFRP‐Al sheets in automobile lightweighting technologies: A review

“…[ 5 ] The schematic of laser surface treatment is shown in Figure 1. Çoban et al [ 6 ] obtained the surface patterns of different laser scribes through CO 2 laser treatment to study the influence of surface structure on the adhesive bonding strength of carbon fiber composites. The mechanical interlocking mechanism can be obtained by optimizing the laser scribing mode to improve the strength of CFRP joint.…”

Effect of surface treatment on the performance of composite‐composite and composite‐metal adhesive joints

“…These surface treatment creates macro roughness on composite surface, causes poor adhesion, are labor‐intensive, and etch the surface heterogeneously. [ 18 ] Sezer [ 15 ] reported that chemical etching is an alternative route for the modification of composite surfaces in the microelectronic industry. These etchants interact with the polymer matrix physically, etch the surface homogenously, and create micromechanical interlocking between the adhesive and composite surface.…”