Inline additively manufactured functionally graded multi-materials: microstructural and mechanical characterization of 316L parts with H13 layers

In the current work, a functionally graded multi-material consisting of stainless steel 316L and hot work tool steel H13 has been fabricated by additive manufacturing (AM). Due to the modification of the recoating apparatus, a lean, multi-material AM process can be achieved via inline selective laser melting. The generated functionally graded specimens are characterized by an equiaxed grain growth at the interfaces of the steel layers, which results in excellent bonding of both constituents. Concerning the mechanical properties, tensile tests confirm that failure occurs within the material layer exhibiting the lower tensile strength. Further, this work analyzes microstructural developments in the melt pools which can predominately be described by the Marangoni effect.