Influence of Interlayer Thickness (Zn) on the Properties of Al 7020 FSW Joints

Abstract

The use of lightweight materials in the production of cryogenic tanks, spacecraft body etc. are becoming the need to develop dissimilar metal FSW joints. Friction stir welding (FSW) is a novel and inspired light metal joining process since it is not involved with the melting of the parent metal. In this work, two Aluminium 7020 plates were welded with Zn as an interlayer, using friction stir welding method. Different joints were made by varying the thickness of interlayer (Zn) and thereafter the characterization is done against mechanical properties and microstructure of weld nugget. The test result shows that the specimen joint with 10µ Zn interlayer has higher mechanical properties than samples made with 5µ, 10µ, 20µ, 40µ and 100µ Zn interlayer. To analyze the cause, further optical studies (Image analyzer and SEM analysis) were carried out and found the interlayer dispersion plays a vital role in weld strength. As a conclusion addition of Zinc interlayer with preferable thickness (10µ) in Al7020 FSW joints improve tensile strength and hardness than the FSW joints made with higher and lower interlayer thickness.

A Comparative Study on Fatigue Response of Aluminum Alloy Friction Stir Welded Joints at Various Post-Processing and Treatments

“…FSW structures are often subjected to severe repetitive loadings in service, causing abrupt failure due to the fatigue phenomenon. In an attempt to improve the fatigue resistance of friction stir welded joints, researchers have proposed several techniques including adding nano/micro particles to the weld nugget to create a local metal matrix composites (MMCs) [4][5][6][7], optimizing welding process parameters [8][9][10][11][12] through tool shape and operation rate, introducing novel welding tools with different geometrical features [13][14][15][16][17], inducing compressive residual stresses by means of different methods of cold working [18][19][20][21][22][23], and weld joint post-heat treatment [24][25][26].…”

“…Further techniques [4][5][6][7] improved the mechanical properties of the joints through the addition of sufficient amounts of powders/particles into the stirred zone (SZ) of FSW/FSSW joints. Enami et al [4] added alumina particles to the nugget zone of FSSW aluminum 2024-T3 joints.…”

“…They showed that addition of well-dispersed SiC powder in the SZ of the weld region could improve tensile strength and fatigue life of joints significantly. Through inserting thin metallic foils between the faying surfaces of Al 7020 weld segments, as shown by Lenin et al [7], particles of the foil material were dispersed in the SZ followed during the FSW operation, leading to an improvement in mechanical properties of joints. They showed that the alloying process through dispersing a 10 µm zinc foil in the weld region of Al 7020 FSW joints could enhance the tensile strength and impact energy of test specimens.…”

Design and Development of Semi-Automated Clip Bracket in Automotive

“…In our company fuel filler bracket assy is assembled with 3 main components which include 2 metal components stamped from 200TON NC stamping press and a plastic component that comes from 110TON injection moulding [1][2][3][4][5][6]. After stamping it goes to plating namely EBB plating and the mould parts go to laser printing for customer identification after injection moulding [7][8][9][10][11]. The 3 parts assembled by the manual method in PHA assy shop and are moved to our customer end.…”

Eliminating Wrong Spot Welding by Robots in Production Line

“…Motoman has announced a dedicated welding controller ( with a servo or air gun. Internal extraction eliminates the need for support and the outer band rotation [11][12][13][14][15][16].…”