Effect of interlayer laser shock peening on residual stress induced by selective laser melting

Laser shock peening (LSP) is a surface-strengthening technique that reduces residual stress in metallic parts. However, there is little literature on interlayer LSP strengthening during selective laser melting (SLM). To systematically investigate the effect of LSP on SLM residual stress, we established the removable LSP impact model based on the SLM multiple deposition layers. The mechanism by which the LSP parameters affect the residual stress of SLM is revealed. The results show that the residual tensile stress of SLM transferred to residual compressive stress due to LSP. The peak pressure of LSP is the most crucial factor for determining the residual stress field. The overlap has the second highest effect on the residual stress field due to the higher overlap causing the LSP to be repeatedly impacted at the same location. The effect of LSP diameter and full width at half maximum (FWHM) on residual stress is not as prominent as the first two. However, the appropriate LSP diameter and FWHM can reduce the residual stress hole phenomenon. This work is instructive for eliminating and controlling residual stress in metallic parts manufactured by SLM.

Automated summary

This study systematically investigated the effect of laser shock peening (LSP) on residual stress in selective laser melting (SLM) by establishing a removable LSP impact model. The results showed that LSP can transfer residual tensile stress to compressive stress in SLM. The peak pressure of LSP and the overlap were the most crucial factors determining the residual stress field, while the LSP diameter and FWHM had less prominent effects.