Enhance the microstructure and mechanical properties of directed energy deposition-Arc (DED-Arc) stainless steel 308L using laser shock peening process

Abstract

This study explores the effects of laser shock peening and deposition direction (uni-directional and bi-directional), evaluated with three different build regions, such as bottom (BR), middle (MR), and top regions (TR). In addition, the impact of LSP on microstructure and mechanical properties of SS308L material fabricated using directed energy deposition-Arc (DED-Arc) was studied. The novelty of this work lies in the comparative analysis of LSP-treated versus untreated SS308L samples and its impact on enhancing mechanical performance. LSP treatment significantly improved UTS, YS, hardness, and reduced porosity of the material, with bi-directional deposition samples showing the highest improvements. In the comparison analysis of two different depositions with LSP on top regions, it has been observed that the microstructure of the DED-Arc-created SS308L material was vertically growing columnar and equiaxed interdendritics, and further refined the grain structure by LSP process. Microstructural analysis revealed a refined grain structure with vertically growing columnar and equiaxed dendrites after LSP treatment, enhancing the material’s overall performance. These results suggest that LSP significantly enhances the mechanical properties of DED-Arc-manufactured SS308L, making it a promising technique for improving material quality in additive manufacturing. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.