Laser shock processing with two different laser sources on 2050-T8 aluminum alloy

• Published in: International journal of structural integrity 2011-01, Vol.2 (1), p.87-100
• Main Authors: Peyre, Patrice, Hfaiedh, Neila, Song, Hongbin, Ji, Vincent, Vignal, Vincent, Seiler, Wilfrid, Branly, Stephane
• Format: Article
• Language: English
• Subjects: Aluminum alloys; Crack initiation; Pressure distribution; Simulation; Titanium alloys
• ISSN: 1757-9864; 1757-9872
• DOI: 10.1108/17579861111108644

Purpose - The purpose of this paper is to conduct a comparative study of the surface modifications induced by two different lasers on a 2050-T8 aluminum alloy, with a specific consideration of residual stress and work-hardening levels.Design methodology approach - Two lasers have been used for Laser shock peening (LSP) treatment in water-confined regime: a Continuum Powerlite Plus laser, operating at 0.532 mm with 9 ns laser pulses, and near 1.5mm spot diameters; a new generation Gaia-R Thales laser delivering 10 J-10 ns impacts, with 4-6mm homogeneous laser spots at 1.06 mm. Surface deformation, work-hardening levels and residual stresses were analyzed for both LSP conditions. Residual stresses were compared with numerical simulations using a 3D finite element (FE) model, starting with the validation of surface deformations induced by a single laser impact.Findings - Similar surface deformations and work-hardening levels, but relatively lower residual stresses were obtained with the new large 4-6 mm impact configuration. This was attributed to a reduced number of local cyclic loadings (2) compared with the small impact configuration (4). Additionally, more anisotropic stresses were obtained with small impacts. FE simulations using Johnson-Cook's material' behavior were shown to simulate accurately surface deformations, but to overestimate maximum stress levels.Research limitations implications - This work should provide LSP workers a better understanding of the possible benefits from the different LSP configurations currently co-existing: using small (4-5 mm). Moreover, experimental results and simulated data had never been presented on 2050-T8 Al alloy.Originality value - An experimental (and numerical) comparison using two distinct laser sources for LSP, has never been presented before. This preliminary work should help LSP workers to choose adequate sources.