Effect of Multiple Laser Shock Peening without Coating on Al-2024-O Alloy for Automotive Applications

The present work discusses the influence of surface compressive residual stress induced by multiple laser shock peening without coating process using low energy Nd: YAG laser with the fundamental wavelength. Laser shock peening without absorbent coating (LSPwC) was employed to Al-2024 in order to improve its surface microstructure and mechanical properties. The compressive residual stress measurements are accomplished according to X-ray diffraction sin2Ψ method. The surface morphology and roughness analysis were carried out using atomic force microscope and roughness profilometer respectively. Also, the microstructure analysis was performed using an optical microscope and scanning electron microscope. The Vickers micro-hardness revealed the improvement of surface and sub-surface hardness after multiple laser shock peening without coating process using low energy laser.