Effects of laser shock peening on the mechanisms of fatigue short crack initiation and propagation of AA7075-T651

A. G. Sanchez, C. You, M. Leering, D. Glaser, D. Furfari, M. E. Fitzpatrick, J. Wharton, P. A.S. Reed

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

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 languageEnglish
Article number106025
JournalInternational Journal of Fatigue
Volume143
Early online date1 Nov 2020
DOIs
Publication statusPublished - 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

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