Laser Shock Peening (LSP) is a surface treatment technique that induces significant compressive residual stresses (CRS) in metal. During LSP processing, high-energy nanosecond laser pulses generate shock waves on surface. These waves propagate through the material, causing plastic deformation in the surface layer and producing CRS with amplitudes reaching -1 GPa and depth more than 1 mm. To investigate LSP, an experimental setup was developed enabling real-time measurement of pressure pulse profiles and subsequent reconstruction of through-thickness CRS distributions. Two fatigue tests were carried out to demonstrate LSP’s effectiveness while highlighting the need for careful application: one involving stress-concentrated plate samples (high-cycle fatigue) and another using cylindrical samples (gigacycle fatigue regime). For stress-concentrated samples, LSP significantly increased fatigue life. Conversely, in gigacycle fatigue tests, LSP reduced the fatigue limit by three orders of magnitude due to significant internal tensile residual stresses generated within the specimen volume.
Plekhov et al. (2026) studied this question.