3. Results and discussion
3.1. Surface morphology observations
The multiple impacts of shot have influence on the surface integrity of shot peened samples, representing many
dimples. Surface SEM observations of non-peened, shot peened specimens were shown in Fig. 3.
Fig. 3(a) shows the surface morphology of not peened Al-Li alloy, the surface is smooth and the material flow
direction of fiber texture can be seen. Fig. 3(b) shows the surface morphology of shot peened Al-Li alloy, there is a
certain increase on surface roughness. There is a certain degree of damage in the surface of Al-Li alloy after shot
peening, local delamination and chapped phenomenon appear around the crater. Although shot peening can
improve the mechanical properties of the material, but also may hurt the integrity of the material surface.