Experimental Study the Effect of Tool Design on the Mechanical Properties of Bobbin Friction Stir Welded 6061-T6 Aluminum Alloy. alkej [Internet]. 2018 Sep. 15 [cited 2025 Jan. 2];14(3):1-11. Available from: https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/85