The effects of friction stir welding on the mechanical properties and microstructure of 7000 series aluminium tailor-welded blanks

The mechanical properties and microstructure of Friction Stir Welded (FSW) tailor made blanks from 7000 series alloys is studied in this paper. The 7075-T6 alloy is selected for the study and three different thicknesses of this alloy are welded together to make tailor-made blanks with three different thickness ratios, i.e. 1, 1.3, and 1.7. The microstructure, hardness profile, global mechanical properties (in aswelded and machined conditions), and local mechanical properties (captured by Digital Image Correlation (DIC) method) of the welds are presented. It has been shown that though in all cases the strength and formability of the welded blanks are lower than those of the base metals, other factors such as the thickness ratio play an important role in this regard.