Influence of the cooling behaviour on mechanical properties of carbon fibre-reinforced thermoplastic/metal laminates

Abstract

For several years, thermoplastic hybrid laminates form a new class in the field of material compounds. These laminates consist of fibre-reinforced plastic prepregs and metal layers in alternating order. Compared to conventional thermosetting multilayer composites, these laminates are suitable for large-scale production and can be manufactured with significantly reduced cycle times in the thermoforming process. In the framework of this contribution, the influence of the cooling rate of carbon fibre-reinforced thermoplastic composites and hybrid laminates was investigated with regard to crystallinity and the resulting mechanical properties. Polyamide 6 and thermoplastic polyurethane as matrix systems were examined, in particular.Additionally, the differential scanning calorimetry was used in order to investigate the influence of the cooling rate on the crystallisation behaviour. It could be determined that the cooling rate has a limited influence on the crystallisation of polyamide 6 and this influences the mechanical properties. Furthermore, a reliance of process parameters on the characteristics profile of composite materials and material compounds with thermoplastic polyurethane could be identified. Depending on process conditions, tensile, bending, and interlaminar shear properties fluctuate up to 20 % in fibre-reinforced laminates and up to 32 % in hybrid laminates. Moderate to fast cooling rates result in optimum mechanical characteristics of tensile properties in fibre-plastic-compounds. Fast to very fast cooling rates are advisable for bending and interlaminar shear properties. Highest tensile and bending characteristics are achieved in hybrid laminates by using fast to very fast cooling rates, while interlaminar shear properties tend to be highest in slow to moderate cooling rates.

CATPUAL - An Innovative and High-Performance Hybrid Laminate with Carbon Fibre-Reinforced Thermoplastic Polyurethane

“…The determination of the fibre volume contents was made with the thermogravimetric analysis, following the DIN EN ISO 11358. A characterisation of the mechanical behaviour of selected thermoplastic Ce-Preg ® FRP was already established in [9,10,11,12].…”

“…As an alternative to matrices thermoplastic polyurethane (TPU) present themselves, Engineering TPUs in particular. The potential of carbon fibre-reinforced TPU laminates was already publicised in [9,10].…”

Introducing Fractal Dimension for Interlaminar Shear and Tensile Strength Assessment of Mechanically Interlocked Polymer–Metal Interfaces

“…The joining technique determines the time-temperature-pressure regime. According to Zopp et al [2], the cooling rate influences the crystallization and the related mechanical properties of the polymer within the melting zone. Katayama and Kawahito [3] investigated direct laser heating of the interface zone using transparent polymer.…”