Numerical Study on Laser Shock Peening of Pure Al Correlating with Laser Shock Wave

Abstract

Laser shock peening (LSP) is an innovative and promising surface strengthening technique of metallic materials. The LSP-induced plastic deformation, the compressive residual stresses and the microstructure evolution are essentially attributed to the laser plasma-induced shock wave. A three-dimensional finite element model in conjunction with the dislocation density-based constitutive model was developed to simulate the LSP of pure Al correlating with the LSP-induced shock wave, and the predicted in-depth residual stresses are in reasonable agreement with the experiment results. The LSP-induced shock wave associated with the laser spot diameter of 8.0 mm propagates in the form of the plane wave, and attenuates exponentially. At the same time, the propagation and attenuation of the LSP-induced shock wave associated with the laser spot diameter of 0.8 mm are in the form of the spherical wave. The reflection of the LSP-induced shock wave at the bottom surface of the target model increases the plastic deformation of the target bottom, resulting in the increase of dislocation density and the decrease of dislocation cell size accordingly. Reducing the target thickness can significantly increase the reflection times of the LSP-induced shock wave at the bottom and top surfaces of the target model, which is considered to be conductive to the generation of the compressive residual stress field and grain refinement.

Cavitation Erosion Prevention Using Laser Shock Peening: Development of a Predictive Evaluation System

“…The probable reason for that is: 1. Boundary conditions, where the infinite element is set at the model borders, have been frequently employed in LSP simulation studies to prove their viability [ 22 , 26 ]. But the infinite element performance in CE simulation, a new finite element study field, is unclear.…”

“…Laser Shock Peening (LSP), an advanced technique widely used in aerospace and other critical military fields, has gained a lot of attention in the field of cavitation erosion resistance in recent years [ 14 , 15 , 16 , 17 ]. The principle of LSP technic is using laser beams to generate plasma shock waves to act on metallic materials to improve their fatigue and corrosion resistance [ 18 , 19 , 20 , 21 , 22 ]. S. Zabeen et al used LSP to study the residual stress field around aero-engine specimens.…”

Precisely tuning the residual stress anisotropy in machine hammer peening

“…The surface modification processes can improve the structure's fatigue performance by producing a profile of near-surface residual compressive stress (RCS) [3]. Many surface modification processes come into being according to this concept, including shot peening (SP), laser shock peening (LSP), deep rolling (DR), ultrasonic surface rolling process (USRP), et al [4,5,6,7]. SP and LSP can induce a certain RCS at the subsurface, but the treated sample is usually left with high surface roughness [8,9].…”