Review on the advancements and relevance of emerging joining techniques for aluminium to polymers/carbon fibre-reinforced polymer lightweight hybrid structures

The demand for higher fuel efficiency and low fuel pollution rates leads to the development of lightweight hybrid structures. The predominant aim is to develop innovative light products with extreme versatility with bionomic and economic balance. Lightweight materials in the structures have successfully solved these problems in many industries, especially automobiles and aerospace. There is an emerging scope in producing automotive components by joining Al and Mg-based alloys with materials such as thermoplastics, ceramics and fibre-reinforced composites. Developing hybrid structures by employing metal-polymer joining is still a significant challenge. There are as many joining techniques available for joining metal with a polymer. Owing to certain drawbacks, some methods are ineffective, such as high processing time for adhesive bonding and mechanical fastening due to increased weight. The friction-based welding technique benefits hybrid joining due to its low heat-affected zone with less metallurgical damages. The study provides an overview of many emerging technologies for joining aluminium to thermoplastic/carbon fibre-reinforced polymer for lightweight structures. The paper compares different joint configurations and the effect of process variables on the microstructural and mechanical properties of hybrid joints. In addition, attempts are made to comprehend contemporary developments in the finite element simulation studies of hybrid structures. The paper also highlights recently developed strategies and gaps in areas where future studies might be focussed. Thus, the paper gives an overview of the advancements and relevance of the emerging joining technique for aluminium to polymers/carbon fibre-reinforced polymer hybrid structures.