Influence of the manufacturing sequence on the microstructure and mechanical properties of hybrid 316L and 17-4 PH walls manufactured with DED-Arc/M

The DED-Arc/M (DED: direct energy deposition; Arc: arc as energy source; M: metallic material) process utilises the arc welding process for the additive manufacturing (AM) of components. This offers the possibility of producing so-called functionally graded additive manufacturing (FGAM) structures. The aim of the present study is to illustrate the dependence of microstructural and mechanical properties on the manufacturing sequence of hybrid materials made from the high-alloy stainless steels 316L and 17-4 PH. For this purpose, GMAW-DED-Arc/M was used to produce vertical multilayer walls consisting of monomaterial 316L, a resulting transition zone and monomaterial 17-4 PH in the build-up direction. Micrographs and EDX analysis show a transition zone over three consecutive layers, when the respective filler material is exchanged. Microhardness tests of the transition zone show an abrupt change for both production sequences, whereby the hardness is similar to that of 316L or 17-4 PH. Tensile tests were used to determine the mechanical properties of the materials in the build-up direction. In the test, the hybrid components each failed in the region that consists of the material 316L, whereby the strengths are in the range of previous literature data and are not dependent on the manufacturing sequence.