Frattura ed Integrità Strutturale (Mar 2019)
Development of hybrid friction stir welding and adhesive bonding single lap joints in aluminium alloys
Abstract
Aircraft have been manufactured for decades using a wide variety of welding and joining techniques. There have been significant developments in techniques over the last 15–20 years. In civil aeronautical industry the main materials used for the fuselage and structural parts are aluminium alloys. In order to reduce weight, leading to a better fuel and economic efficiency, there is the need to find innovative solutions to join aluminium components in a single lap joint (SLJ) configuration with higher strength to weight ratio than riveting and fastening. In this work, a combination of the friction stir welding (FSW) and adhesive bonding (AB) processes is presented. Quasi-static mechanical properties, fatigue behaviour and other properties of the friction stir weld-bonding joints were assessed and compared with adhesive only and friction stir welded only joints. The development of this new joining technology, the combination of FSW with AB, forming friction stir weld-bonding, aims to incorporate properties and characteristics of both joining technologies, as well as improving damage tolerance. The present research involved the production of two types of overlap joints - FSW and hybrid friction stir weld-bonding. The main objective of this study is to compare the different joining technologies in lap joint configuration and evaluate the influence of different parameters on the mechanical behavior of the joints. The hybrid joints present better overall results, and the best joint was efficiency achieved with the hybrid joint produced with 450 kgf. The average efficiency value in this case was 73.75%, however in a particular specimen it reached the value of 85.21%. From the results it is possible to affirm that the hybridization process confers an improvement between 20-30 % in most cases.
