Effect of build height on the properties of large format stainless steel 316L fabricated via directed energy deposition

Directed energy deposition (DED) is a promising technique for cladding and repair due to its ability to deposit molten metal onto existing surfaces. To date, much still needs to be understood regarding the microstructure evolution during DED. The work herein seeks to reveal the effect of build height on mechanical properties and corrosion for austenitic stainless steel 316L. A large 316L block was fabricated via DED and horizontal tensile specimens were taken from every 3 mm along the build height in order to assess the effect of build height on the mechanical response. Electron backscatter diffraction mapping was also conducted on sections taken from the bottom, middle and top heights of the build, to assess the microstructural evolution. Cyclic polarisation testing was performed on sections from the build to assess the pitting potential and re-passivation as a function of build height.