Effect of selective laser melting (SLM) process parameters on microstructure and mechanical properties of 316L austenitic stainless steel

Metal components produced via selective laser melting (SLM) additive manufacturing (AM) can offer comparable and sometimes superior mechanical properties to those of bulk materials. Selection of the appropriate process parameters (e.g. laser power, build direction, scan hatch spacing) plays a fundamental role in determining final properties. For this reason, microstructure, defect formation and mechanical properties of AISI 316L components are investigated in this paper according to the process parameters used for their fabrication. A first experimental campaign establishes process parameters guaranteeing a density greater than 98%. Samples for microstructural and mechanical characterization are then produced based on these results, varying laser power from 100 W to 150 W, hatch space from 0.05 nun to 0.07 mm and orientation from 45 degrees to 90 degrees. A MYSINT100 SLM machine with laser power up to 150 W and spot diameter of 50 mu m is employed for all experiments. The presented results establish a correlation between the process parameters and the resulting microstructure and mechanical properties of SLM 316L specimens.