Peening coverage has essential effects on the service performance of parts. In this paper

aluminum alloy 2024–T351 was subjected to pneumatic shot peening with different coverage of 88.3%

100%

200% and 400% by adjusting feeding speed. The surface topography and microstructure

roughness

residual stress and microhardness were investigated using a scanning electron microscope

roughness tester

residual stress instrument and Vickers hardness tester. The surface roughness increases first and then decreases with the increase of peening coverage. The average surface roughness of peened sample with 100% coverage is 4.601 μm

which is the highest value. Moreover

the peened surface shows significant folds and microcracks owing to the high coverage of 400%. The increase of peening coverage leads to the enlargement of the maximum compressive residual stress and depth of the compressive residual stress layer. Similarly

the maximum hardness and hardened layer depth are enhanced with peening coverage. The maximum hardness corresponding to peening coverage of 88.3%

100%

200% and 400% is increased by 18.4%

22.8%

25.1% and 27.2%

respectively.