Effect of welding parameters on tensile properties and fracture behavior of friction stir welded Al–Mg–Si alloy

Al–Mg–Si alloy plates friction stir welded at a tool traverse speed of 400 mm/min exhibited higher tensile strength with 45° shear fracture, whereas lower tensile strengths with nearly vertical fractures were observed for samples welded at a lower speed of 100 mm/min. The fracture paths corresponded well with the lowest hardness distribution profiles in the joints. The heat indexes cannot be used as parameters to evaluate the thermal input, mechanical properties and fracture mode.