Influence of post-processing methods on the fatigue performance of materials produced by selective laser melting (SLM)

Despite the capability to fabricate complex and customized products, selective laser melted (SLMed) parts exhibit reduced fatigue performance compared to wrought counterparts. The imperfections resulting from suboptimal manufacturing parameters and the inherent drawbacks of the process are the predominant factors contributing to this disparity. The scatter in fatigue property persists regardless of using optimal manufacturing parameters. However, employing post-processing methods to mitigate or eliminate defects has proven to be an effective approach for improving fatigue performance. In this paper, diverse post-processing methods that could be utilized as leverage to alter the surface and subsurface defects and internal imperfections are copiously covered. Each method exhibited diverse potential in developing beneficial compressive residual stress (CRS), surface and subsurface defect alteration, and fatigue performance improvement. Considering the cycling routine, the impact of distinct post-processing methods was found to vary, and contradictory findings that necessitate clarification are investigated in this article. Furthermore, an in-depth review is conducted to identify the types and features of defects that could influence fatigue performance, emphasizing the need to comprehend these imperfections. The paper identifies research gaps in existing post-processing methods and delineates future research direction, spotlighting underutilized yet potentially transformative techniques.