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This paper presents the results of studying friction stir butt welding of commercial pure copper plates using both experimental and finite element analysis methods. The experimental work consisted of making a butt joint to 4 mm copper plates using friction stir welding process at constant rotational speed of the pin tool to evaluate the effect of welding speed on weld quality. Weld quality was evaluated by the joints tensile strength, micro hardness, as well as evolution of the developed microstructure across the welding zone. A coupled Eulerian Lagrangian (CEL) finite element (FE) model had been developed to simulate the friction stir butt welding process, and predict the temperature distributions across the weld, as well as developed welding stresses. Axial load and temperature measurements results from the experiments have been used to validate the finite element model.

Welding of copper and aluminium has been problematic with tradition fusion method. The friction stir welding (FSW) was employed to butt weld the T2 copper and 1061 aluminum alloy plates. The welding parameters were planned by the orthogonal experiment design method. The samples obtained in experiments were investigated in the aspects of microstructure, tensile strength, fatigue performance and micro-hardness.Sound weld with the best tensile strength and fatigue life was produced under the welding parameters of rotation speed, 1100rpm and welding speed 50mm/min. The tensile strength was 193.16MPa, 85% of the base aluminium material. Three intermetallic compounds (IMC) of CuAl, Cu3Al and Cu9Al4 were detected at the copper-aluminium interface in XRD analysis.

A novel approach for predicting the intermetallic compound formation during friction stir welding of AA6061 to commercially pure copper has been developed, in addition to their effect on mechanical properties. The temperature distribution of the aluminium to copper weld nugget determined by a finite element model, the use of an Al-Cu phase diagram and the elemental concentration of copper and aluminium in the weld nugget have been combined to predict and validate several intermetallic compounds present in the different zones of the weldment. The results of performing butt-welding of these dissimilar metals using the friction stir welding process demonstrated that the highest ultimate tensile strength of 194.5 MPa was achieved at 1500 rpm tool rotational speed, 100 mm/min traverse speed and a zero-tool offset.

Friction stir spot welding (FSSW) is an appropriate process to join materials that are difficult to weld using fusion welding, such as copper. In this paper, an experimental study to weld lap joint of pure copper plates having a dimensions of 100 × 30 × 2 mm is performed, successful spot weld is obtained at tool rotational speed of 1200 rpm, feed rate of 20 mm/min for dwell time of 2 seconds. The tool used in the FSSW has a threaded pin of 5 mm diameter, length of 3.7 mm, and a scrolled shoulder of 11.52 mm diameter. Tensile test and microhardness were performed for the joint and it showed reasonable weld strength. In addition, a numerical model was developed, and the estimated temperatures as well as weld macrostructure matched very well with experimental results.