Rapid direct thermal joining of aluminium alloys and thermoplastic carbon fiber reinforced polyamides by means of NIR-radiation: Influence of pre-treatment and joining process parameters on the joint strengthWednesday (29.04.2020) 14:40 - 15:00 Room 2
Today hybrid joints made of metal and fiber reinforced plastics (short FRP) such as carbon and glass fiber based ones are applied across all industries. Suitable lightweight materials are combined with each other in order to make targeted use of their specific benefits within one construction. Hybrid structures (e.g. metal-composites) are developed, which significantly contribute to resource efficiency in different industries such as automobile and aircraft industry by weight reduction. For such innovative multi-material designs the assembling of the different materials is critical because for each of the different material combinations a specially adapted and efficient joining technology is required. For state-of-the-art joining technologies, like mechanical joining by screws or rivets and adhesive bonding, specific restrictions can be found with the use of additional material, limitations in the geometric flexibility or comparable long bonding times.
The aim of this work is to develop a fast and economic joining technique of carbon fiber reinforced thermoplastic polymers (short: CFRTP) and an aluminium alloy (EN AW-7075 T6). In this presentation, investigations for a suitable homogeneous temperature and pressure range are presented. To increase the mechanical interlock and to clean the surface, the aluminium was structured with a short pulse N-IR-laser. Thereby, different surface topographies with a characteristic aspect ratio range of 0.1 to 2.0. The achieved surface conditions were characterized by optical methods and correlated with mechanical properties of the produced single-lap joints. The results indicate that by usage of a specific range of N-IR-laser parameters the shear strength under tensile load can be increased up to a maximum value corresponding to the interlaminar shear strength (short ILS) value of the starting CFRTP material.