Influence of Grain Boundary on the Fatigue Crack Growth of 7050-T7451 Aluminum Alloy Based on Small Time Scale Method

Figure 5

In the loading stage of 99 cycles, micromorphology of fatigue crack at different loading level: (a) at 540 N, (b) at 960 N, (c) at 1380 N, and (d) at 1750 N.

(a)

(b)

(c)

(d)