Abstract
A laser shock peening (LSP) treatment was performed on AA7075-T651 for maximum fatigue improvement. Surface and microstructural characterisation techniques (micro-hardness, SEM-EBSD, contact-profilometry) showed LSP surface modification was limited, and LSP generated deep compressive residual stresses above −300 MPa. Fatigue testing showed a two-order magnitude increase in overall life, due to the mechanism of crack initiation changing from surface second-phase particles to subsurface crack initiation dependent on the local stress field. Modelling highlights the sensitive balance between surface roughness (including LSP-induced pits) and residual stress on the micro-mechanism of crack initiation, and how this can be used to maximise fatigue life extension.
Original language | English |
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Article number | 106025 |
Journal | International Journal of Fatigue |
Volume | 143 |
Early online date | 1 Nov 2020 |
DOIs | |
Publication status | Published - Feb 2021 |
Funder
Engineering and Physical Sciences Research Council (EPSRC), UK (Grant EP/N509747/1 )Keywords
- Aluminium alloys
- Fatigue initiation
- Micromechanics
- Surface flaws
ASJC Scopus subject areas
- Modelling and Simulation
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering
- Industrial and Manufacturing Engineering