Directed Energy Deposition Additive Manufacturing of Stainless Steel with Spatially Variable Process Parameters

This study investigates the effects of spatially varied process parameters (SVPP) on the microstructural and mechanical properties of stainless steel 316L (SS 316L) fabricated using directed energy deposition (DED) additive manufacturing. Conventional DED builds typically employ a single global parameter set throughout the part, which amplifies the sensitivity of melt pool behavior to evolving thermal conditions and often leads to uncontrolled fluctuations in thermal history, microstructural heterogeneity, and anisotropic mechanical response. To mitigate these issues, this work explores how real-time, intentional variation of DED parameters across both vertical and horizontal planes can tailor and control microstructure and mechanical behavior within a single-material component. Hardness and tensile strength increased across both vertical and horizontal gradients, validating that SVPP can engineer functional zones within a single component. The study highlights the potential of SVPP as a cost-effective strategy to enhance the versatility and functional capability of DED-processed components. These findings lay the foundation for application-specific manufacturing, particularly in aerospace, motorsport, and biomedical fields, where control over local mechanical response is critical.