681910.fig.004a
(a)
681910.fig.004b
(b)
681910.fig.004c
(c)
681910.fig.004d
(d)
Figure 4: Microstructures of (a) 5052H32 base material, (b) 6061T6 base material, (c) weld zone constituting FS welded sheets made of 5052H32-6061T6 at the welding condition: shoulder diameter: 18 mm; welding speed: 80 mm/min; rotational speed: 700 rpm, and (d) weld zone constituting FS welded sheets made of 5052H32-6061T6 at the welding condition: shoulder diameter; 18 mm; welding speed: 100 mm/min; rotational speed; 800 rpm.