Influence of energy input and interpass temperature on the mechanical properties of DED-arc manufactured 316L stainless steel

Abstract Directed energy deposition-arc (DED-arc) provides a process with high deposition rates for the additive manufacturing of metal components. Due to the close coupling of material and energy input, especially in gas metal arc welding (GMAW) process variants, different deposition rates lead to varying thermal conditions during material deposition, which in turn influence the resulting properties of the final component. For steels, high thermal cycles can lead to a degradation of the mechanical properties. This study presents the influences of energy input and interpass temperature on the mechanical properties in DED-arc manufacturing of AISI 316L stainless steel. Thin-walled structures were additively manufactured under variation of energy input and interpass temperature, from which specimens for metallographic investigations and tensile tests were subsequently extracted. Regarding possible material anisotropies, the tensile tests were carried out in three different loading directions in relation to the build-up direction. The results show pronounced grain growth and associated softening zones in the build-up direction, the extent of which depends on the process parameters. At moderate energy inputs and interlayer temperatures, this leads to distinct anisotropic properties with beneficial mechanical properties diagonal to the build-up direction. Higher thermal cycles result in increased softening zones and thus less anisotropic material behavior with slightly lower yield limit and elongation.