Study on Material Flow Behavior in Three-Dimensional Directions During Friction Stir Welding and the Establishment of a Qualitative Model. - Wei, Cheng-Gang; Lu, Sheng; Chen, Jun; Zhang, Jun; Zhu, Jin-Ling; Gridasov, Alexander V.; Statsenko, Vladimir N.; Pogodaev, Anton V. (Materials (1996-1944), 2026)