Colloquia

Summary

The share of thermoplastics composites in de automotive and aerospace industry is increasing significantly by replacing thermoset composites. The introduction of these materials came with developments of new joining techniques like co-consolidation. The co-consolidation allows metal-TPC hybrid joints to be bonded without use of third components like fasteners and adhesive.

The performance of the co-consolidated hybrid interface depends on a variety of bonding mechanisms.  Metal surface treatment is essential to enhance the interface performance by promoting mechanical interlocking as bonding mechanism.  Several surface treatments are known for enhancing the interface performance of metal-TPC hybrid joints by surface modification. With the arrival of additive manufacturing, products can be created with modified surfaces directly integrated in the production process. This enables a unique production process resulting in potential shorter production times and improvement of hybrid interface performance. 

The objective of this research is to investigate and optimize the interface performance of a co-consolidated functionalized SS316L surface and C/PEEK hybrid joint.

The focus was to functionalize a SS316L surface by selective laser melting processing, creating interlocking features to optimize the interface performance of a C/PEEK -SS316L hybrid joint. In this research different surface topologies have been created by different proposed SLM process parameter sets, varying the build orientation and functionalised layer thickness. These surface topographies have been evaluated by morphology analysis, surface characterization and cross-section analysis. With the use of co-consolidation hybrid bonds between functionalised SS316L substrates and C/PEEK UD tape were created. Furthermore, the addition of extra PEEK film was varied between samples sets to investigate the effect on the fracture toughness and co-consolidation quality. The hybrid interfaces created were experimentally evaluated by the mandrel peel test measuring the fracture toughness. Finally, the failure behaviour was analysed.

Results show that interface performance of a hybrid joint is significant improved by functionalisation of SS316L substrates creating interlocking structures using the SLM process. The composition of the SLM parameter sets and build orientation had significant effect on the surface morphology and fracture toughness. Overall, SS316L functionalised substrates have proved to be suitable for co-consolidation as production method. Fracture toughness values were found exceeding the interlaminar fracture toughness measured for C/PEEK UD laminates by significance.