Abstract
AA8011 remains one of the largest used aluminium alloys due to excellent ductility, corrosion resistance and sufficient strength in H14 conditions. The 5754, due to high strength and corrosion resistance finds key applications in marine, process industry, automobile and nuclear applications. A T-joint combination of the two alloys (when stronger forming is stiffeners) results in significant weight savings. The T-joint between 8011 and 5754 (with the latter forming the stringer) is highly prone to defect formation due to the stronger material being placed away from the heat source. In this paper, friction stir welding of AA5754 and AA8011 aluminium alloys in T-lap configuration is performed. Effects of processing parameters namely tool transverse speed, rotational speed and shoulder diameter on the weld properties are studied with the help of micro-hardness, macrostructure and microstructure analysis. Analysis of defects such as tunnel and kissing bond, and mechanism of defect formation is also discussed. Tunnel defect is observed on advancing side in all the samples, which is attributed to high heat flux on advancing side, insufficient material flow in the vertical direction and asymmetric flow of plasticized material from advancing side to retreating side. The size of the defect is found to increase with increase in shoulder diameter keeping the rotational speed constant. Kissing bond defect was also observed in some samples owing to the presence of oxide layer between the joining surfaces.
Highlights
The quest for weight reduction and high strength drive wide applications of Al-alloys in strategic sectors
stir zone (SZ) comprises of very fine grains as it is subjected to severe plastic deformation (SPD) and dynamic recrystallization (DRX) [31,32,33,34]
The successful application of Friction Stir Welded T-joints will result in higher strength to weight ratios of aerospace and automobile structures
Summary
The quest for weight reduction and high strength drive wide applications of Al-alloys in strategic sectors (in fabrication of stiffened panels by attaching stiffeners to skin sheets like in railway rolling stock, airframe structures, car bodies, structures in marine and nuclear power etc.). Skin and stringer are mechanically joined in Tconfiguration. The prevalent joining methods based on mechanical processes are time, capital and skill intensive and increase the weight of assembled joint. Joining by conventional fusion-based welding processes softens the age-hardened alloys, introduces defects such as porosities, high residual stresses and distortion. The advent of solid-state friction stir welding (FSW) process facilitated the joining of difficult to weld or even unweldable materials [1,2]. In FSW of T-joint [3,4], specially
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
