Characterisation of porosity, density, and microstructure of directed energy deposited stainless steel AISI 316L

Abstract

Directed Energy Deposition (DED) was used to form a Stainless Steel AISI 316 L steel block component on a Mild Steel S235JR substrate. Porosity, density, and defect were characterised at 4 localities within the DED component by microscopy and x-ray tomography. Three-dimensional (3D) reconstruction of the x-ray tomographic image sequences focused at select porosities is presented. The element composition and Vickers microhardness measurements were taken at the fusion lines and track body locations to characterise the differences in materials and mechanical properties at the 2 locations. Lastly, an element mapping analysis was conducted to determine the solidification mode for the DED component. Sources for defects were proposed based on the characteristics of the porosity analysis and conclusions were made about the solidification behaviour of the DED component.