37 / 2024-09-04 14:06:07

Effect of Laser Shock Peening on Residual Stress and Microstructure of Laser Additive Manufactured AlSi10Mg Alloy

residual stress,laser shock peeing,Short-wavelength characteristic X-ray diffraction,nondestructive testing,Al alloys

Laser additive manufacturing (LAM) is widely applied in the research and production of components and parts, offering significant advantages in the fabrication of complex structures. However, the rapid cooling speeds involved can lead to high tensile residual stresses, which cause issues such as part deformation, cracking, and reduced fatigue life. Laser shock peening (LSP) is used to modify the residual stress and microstructures of LAMed AlSi10Mg alloy. surface and near-surface residual stress was non-destructively tested using an innovative Short Wavelength Characteristic X-ray Diffraction technique and X-ray diffraction. The test results indicate that compressive residual stresses prevailing within 2mm from the surface after LSP. The Vickers hardness within the peened region decreases with depth and is approximately 1.2 to 1.3 times higher than that of the untreated material. The depth of the microhardness-affected zone is around 2 mm, which is essentially consistent with the depth of the compressive residual stress. A significant increase in the density of dislocations is observed in the LSP region. The distribution of low-angle grain boundaries extends to greater depths in the samples subjected to higher LSP energies. LSP result in grain refinement at the surface and samples subject to higher energy treatments exhibiting a more pronounced degree of grain refinement.