metals Article Multi-Track Friction Stir Lap Welding of 2024 Aluminum Alloy: Processing, Microstructure and Mechanical Properties Shengke Zou 1, Shuyuan Ma 1, Changmeng Liu 1,*, Cheng Chen 1, Limin Ma 2, Jiping Lu 1 and Jing Guo 1 1 School of Mechanical Engineering, Beijing Institute of ...