Investigating the effect on the position in advancing and retreating side on the mechanical properties of the joint samples in the friction stir welding of 6061 and 5054 aluminum alloys

Friction stir welding is a new method, which is classified in the category of solid state bonding processes. In such processes during the process, the workpiece and tool materials do not melt, and the process temperature is always at a lower level than the melting temperature. This technique is used to joint aluminum alloys and does not have any restrictions on use such as fusion welding. In the present study, the experimental study of the effect of the position of metal with higher strength on the advancing and retreating side and on the ultimate tensile stress and fine hardness of the samples obtained from the joint specimens by the friction stir welding method. Two aluminum alloys, 6061 and 5054, were used, and each of these alloys was placed in two experimental and two directions on the both sides. By examining the tensile test graphs from the two experimental conditions, it was found that the samples in which the metal with higher strength placed on the advancing side found to have a higher final strength in the welded specimen. When the metal with higher strength in the retreating side was placed, the final strength of the bonded samples from both base alloys was lower and the softness and strain of the break in the samples increased the firmness of the base metals. The micro hardness of both experimental modes was studied and a W-shaped pattern was obtained for both experimental friction stir welding.