Evaluation of load-carrying capabilities of friction stir welded, TIG welded and riveted joints of AA2014-T6 aluminium alloy

Abstract

Purpose Presently, the materials used in light combat aircraft structures are aluminium alloys and composites. These structures are joined together through riveted joints. The weight of these rivets for the entire aircraft is nearly one ton. In addition to weight, the riveted connection requires a lot of tools, equipments, fixtures and manpower, which makes it an expensive and time-consuming process. Moreover, Al alloy is also welded using tungsten inert gas (TIG) welding process by proper control of process parameters. This process has limitations such as porosity, alloy segregation and hot cracking. To overcome the above limitations, an alternative technology is required. One such technology is friction stir welding (FSW), which can be successfully applied for welding of aluminium alloy in LCA structures. Therefore, this paper aims to compare the load carrying capabilities of FSW joints with TIG welded and riveted joints. Design/methodology/approach FSW joints and TIG welded joints were fabricated using optimized process parameters, followed by riveted joints using standard shop floor practice in the butt and lap joint configurations. Findings The load-carrying capabilities of FSW joints are superior than those of other joints. FSW joints exhibited 75 per cent higher load-carrying capability compared to the riveted joints and TIG-welded joints. Practical implications From this investigation, it is inferred that the FSW joint is suitable for the replacement of riveted joints in LCA and TIG-welded joints. Originality/value Friction stir butt joints exhibited 75 per cent higher load-carrying capability than riveted butt joints. Friction stir welded lap joints showed 70 per cent higher load-carrying capability than the riveted lap joints. Friction stir butt joints yielded 41 per cent higher breaking load capabilities than the TIG-welded butt joints. Moreover, Friction stir lap weld joints have 57 per cent more load-carrying capabilities than the TIG-welded lap joints.

Effect of Traverse Speed on the Defect Characteristic, Microstructure, and Mechanical Property of Friction Stir Welded T‐Joints of Dissimilar Mg/Al Alloy

“…Except for the welding speed of 50 mm/min, there are a lot of cleavage surfaces and river patterns on the fracture surfaces of all patterns, which is a typical ductile fracture. EDS results show that the crack is most likely initiated in the Al 3 Mg 2 intermetallic compound layer, which exists at the bottom of MRZ and leads to the initiation of cracks [27]. Figure 19(c) shows that cleavage crack cores are generated at different locations and expand into cleavage facets.…”

Weldability Investigation and Optimization of Process Variables for TIG‐Welded Aluminium Alloy (AA 8006)

“…Usually aluminium alloy welding joints experiments are carried out as per Taguchi method, because Taguchi technique reduces the number of trials and gives optimum results with minimum time and cost [23][24][25][26]. e Design of Experiments (DOE) studied by Taguchi by way of orthogonal arrays (OA) is to improve the process parameters affecting the process with different levels [27].…”

Effect of friction stir process parameters on tensile strength of eggshell and SiC-reinforced aluminium-based composite

“…The joints welded using the 1° and 3° tool tilt angles gave lower shear strength due to unbalanced material flow during FSW in the weld area. In another work, Rajendran et al (2019) identify a mixture of the stir friction parameters such as tool rotational pace, welding speed, tool angle and shoulder diameter to make AA2014-T6 aluminium alloy tensile strength maximal. Tools such as experimental design, variance analysis were used to establish the scientific correlation and to estimate the ultimate tensile strength of the joint at 95% accuracy.…”

“…One is friction stir welding (FSW), an aluminium alloy welding technology that can be used efficiently for light combat aircraft structures (Rajendran et al , 2017). An important insight by experimental analysis has been revealed after going through the literature of Rajendran et al (2019) in which they throw light on the effect on strength and microstructure of FSW for Al alloy AA2014-T6; their findings of were as follows: The tensile shear strength was reduced by 30%. For 1 h with quenching in water and eventual ageing at 170°C for 10 h after friction welding of AA2014-T6 alloy, solid solution treatment at 500°C raises the tensile sheer intensity of the welded joint by 20% relative to its value after welding. …”