Tensile and Fatigue Behavior of Friction-Stir Welded Tailor-Welded Blank of Aluminum Alloy 5754

Friction stir welding is becoming increasingly desirable in many applications, including tailor-welded blanks in which two sheets of different thicknesses are joined together to form blanks that can be subsequently stamped into a final product shape. In this article, we have studied the static tensile and tension-tension fatigue behavior of friction stir welded joint in a tailor-welded blank of aluminum alloy 5754. It was observed that the yield and tensile strengths of friction stir welded specimens with weld located 90° to the tensile direction are close to the base material values, but its elongation is nearly half the elongation for the base material. The friction stir welded joints had relatively high-fatigue strength, and was even superior to that of the base aluminum alloy in the high-cycle region. Pre-straining caused by press forming lowered the elongation to failure, but improved the fatigue performance.