Fatigue properties of wire arc additive manufactured 316L after solution treatment

Abstract Wire arc additive manufacturing (WAAM) components undergo complex thermal cycles during the manufacturing process, leading to microstructural evolution and elemental diffusion. These changes affect the mechanical properties of the components. The fatigue properties of WAAM 316L after solution treatment were systematically investigated in this study, focusing on microstructural characteristics, mechanical properties, and fatigue behavior. Compared to the untreated sample, tensile strength of the solution-treated sample increased by 20.86 % in the horizontal direction and 4.55 % in the vertical direction, respectively. At the microstructural level, the dissolution of dendritic ferrite into the austenitic matrix was facilitated by solution treatment, which resulted in a homogeneous single-phase austenitic structure. After solution treatment, the fatigue strength of WAAM 316L was 41.46 % higher than that of rolled 316L. Fatigue cracks in WAAM 316L primarily initiated from surface or subsurface defects, which indicated that these defects significantly affected the material’s fatigue life. The results indicated that the properties of WAAM 316L was significantly improved by solution treatment. Supported by experimental data, this study provides a basis for optimizing processing parameters and evaluating postprocessing methods of WAAM 316L.