Influence of laser parameters on the depositions of 316L stainless steel using laser powder bed fusion

Laser powder bed fusion (LPBF) is an additive manufacturing technique by which complex structural parts can be built-up in a layer-by-layer process, selectively melting the powder on previously deposited layers. The high energy density applied by the laser beam to a confined volume of powder not only results in high and directional thermal gradients, but also requires extensive calibration to produce uniform melt pools, essential to produce fully dense components. The additive nature of the process and the significant thermal gradients results in a unique microstructure that can be altered by changing the process parameters used. In this work, the melt pool morphology, microstructure and texture of LPBF austenitic stainless steel of type AISI 316L has been characterised by morphological (LOM and SEM),microstructural (SEM and EBSD) and thermal history (thermal cameras, XRD, neutron diffraction) investigations using a variable energy input comparison. The influence of the temperature gradients were also investigated using a combination of XRD and neutron diffraction to evaluate the residual stresses in LPBF-produced parts. The absorbed specific energy used controls the size of the melt pools deposited on the substrate. However, the deposition mode (keyhole mode >150W or conduction mode