Combined effect of process variables on the plastic behaviour of 316L stainless steel printed by L‐PBF

Abstract

The metal additive manufacturing (AM) is a technology that is rapidly spreading in the industrial sector with its enormous potential in making components with complex shapes and low weight, ensuring a high structural strength. However, the mechanical properties of the components depend on the printing process, and the interactions between the process variables and the final material behaviour is still not totally understood. In this work, 12 different types of tensile specimen were built by AM using the laser powder bed fusion (L‐PBF) technique; the used material is the 316L stainless steel. The specimens have the same geometry and the same process parameters in terms of layer thickness, hatch space, laser power, spot diameter, scanning speed and platform preheating temperature, while different laser scan strategies and building orientations are evaluated. The scope is to characterize the plastic behaviour of such specimens and study the differences due to distinct printing strategies. Stereo digital image correlation (stereo‐DIC) was used to evaluate the deformation state and analyse the material anisotropy. Finally, the microstructure and presence of defects were investigated through the optical microscopy (OM) and the scanning electron microscopy (SEM). The analysis shows how the plastic behaviour and the formation of defects are remarkably influenced by the laser scan strategy and by the building orientation.