Aluminum alloys are extensively utilized in critical aerospace structural components

where surface conditions directly impact fatigue life and structural reliability. To investigate the fatigue strength enhancement of typical structures through laser shock peening (LSP) and mechanical shot peening (MSP)

notched specimens of 7050 and 2024 aluminum alloys were prepared. The effects of LSP and MSP on residual stress fields and surface hardness were systematically examined

with subsequent analysis of changes in the detail fatigue strength cutoff (DFR

cutoff

). Key findings include: MSP demonstrat

ed superior amplitude and uniformity in surface compressive residual stress for both alloys compared to LSP

though with significantly shallower affected depths; LSP induced pronounced surface hardening

while MSP provided limited hardness improvement. LSP elevated DFRcutoff of 2024 and 7050 aluminum alloys by 21.9% (163.7 MPa) and 48.1% (175.0 MPa)

respectively

substantially exceeding MSP-treated specimens. For notched structures

LSP generated deeper compressive residual stress layers and higher microhardness

effectively delaying fatigue crack initiation/propagation at stress concentration zones and enhancing fatigue resistance.