681910.fig.005a
(a) 6061T6 base material
681910.fig.005b
(b) For FSW condition: shoulder diameter: 15 mm; rotational speed: 1500 rpm; welding speed: 100 mm/min
Figure 5: Microstructures of (a) 6061T6 base material and (b) friction stir welded sheets made of 6061T6-6061T6 at one particular welding condition.