Experimental Investigation on Micro Friction Stir Welding of Al-Cu

The present study investigated the feasibility of producing strong and defect-free joints between 1050 aluminum and pure copper sheets by micro friction stir welding using ordinary and new tools. By analyzing the results of the tensile test and signal to noise analysis, the average maximum ultimate tensile strength of the joints is reported to be 88 MPa, when using the parameters of rotational speed, traverse speed, and offset of the tool with levels of 2400 rpm, 40 mm/min and 0.25 mm. The variance analysis also showed that the parameters of rotational speed and traverse speed had the most significant effect on the joints' tensile strength. The maximum and minimum values obtained from the microhardness test were recorded for the weld nugget zone and the heat-affected aluminum zone, respectively, equal to 192 HV and 21 HV. The X-ray diffraction test results on optimal samples showed intermetallic compounds such as CuAl2 and Cu9Al4 in the welding area. The tensile strength of the joints created is strongly dependent on the formation of these intermetallic compounds.