That great god can help me analyze the SEM pictures of metal alloys.

It depends on the experimental conditions. Figure 1 has intergranular morphology (upper left corner), and there are many secondary cracks in the figure. Is your load high? Figure 2 is a bit like a dimple, but it doesn't seem to be. I wonder if it's a corrosion pit. The magnification of Figure 3 is too high. Generally, the fatigue band can be seen at 1000 or 2000 times, but it can't be seen. ...