Achieving high property friction stir welded aluminium/copper lap joint at low heat input

Abstract

Aluminium and copper plates with 3 mm thickness were successfully friction stir lap welded at a lower rotation rate of 600 rev min 21 using a larger pin 8 mm in diameter. Good metallurgical bonding on the Al/Cu interface was achieved due to the formation of a thin, continuous and uniform Al-Cu intermetallic compound layer. Furthermore, many Cu particles consisting of pure Cu and intermetallic compound layers were generated at the lower part of the nugget zone, forming a composite structure with increased hardness. A lower rotation rate resulted in a decrease in annealing softening in the heat affected zone (HAZ), and a larger diameter pin increased the Al-Cu bonding area. These factors resulted in that the friction stir welded lap joint exhibited a high failure load of 2680 N with failure in the HAZ on the aluminium side.

Effect of Friction Stir Welding Parameters on the Mechanical and Microstructure Properties of the Al-Cu Butt Joint

“…Due to heat input incrementation and the formation of more intermetallic components at the Al-Cu interface, the brittleness is enhanced and it is considered that this caused a reduction in tensile strength. As introduced in other studies [5,12], a decrease in the tensile strength of the joint happens with the increase in the thickness of the intermetallic phases. The literature shows that intermetallic phases such as Al2Cu, Al4Cu9, CuAl, Al2Cu3 and AlCu4 will occur with the increase in temperature between the aluminum and copper.…”

“…These methods, however, have a few drawbacks. For example, friction welding and roll welding lack versatility, and there are safety problems involved in explosive welding [12]. Several studies have been carried out on the effects of dissimilar aluminum and copper welding parameters on the microstructure and mechanical properties in the weld zone and the detection of intermetallic phases that occurs in the weld zone [5,[13][14][15][16][17].…”

Novel Solid State Cladding of Brass to Steel Plate by Friction Stir Welding

“…Friction Stir Welding (FSW), a solid-state welding process, is well known, and its use for the dissimilar metal joining has been reported on the combination of Al alloy and steel [1,2]; Mg alloy and steel [3]; Ti alloy and steel [4]; Inconel alloy and steel [5]; Al alloy and Mg alloy [6]; and aluminum and copper [7][8][9][10].…”

Effect of Heat Input on the Mechanical Behaviour of Al-Cu FSW Lap Joints

“…Xue et al 4,5 reported that ω is the main responsible for the heat input and, therefore, it is considered by many researchers to be the most important process parameter for the FSW.…”

“…The specimens were obtained for metallographic assessment by cross sectioning the welded joints, which were ground and polished according to standard procedures and chemically etched with a solution containing identical quantities of H 2 O, NH 4 OH and H 2 O 2 for etching the copper part and with a 0.5% hydrofluoric acid solution for the aluminium plate.…”