“…Problems with the conventional fusion welding, limiting the use of the magnesium alloys, could be eliminated by friction stir welding (FSW), which is a solid state welding process [1]. Nowadays, FSW has been widely used to join the magnesium alloys, such as Mg-Al-Zn [2][3][4][5][6][7], Mg-Zn-Y [8,9], and Mg-Al-Ca [10].…”