On the selective laser melting based additive manufacturing of AlSi10Mg: The process parameter investigation through multiphysics simulation and experimental validation

The factor that plays important role in the quality of the final product in selective laser melting (SLM) is the process parameter set used in production. In general, these fabrication parameter sets are obtained experimentally by using the energy density requirements of the material. The experimental investigation is partly a trial and error approach, which is a time and cost-consuming process. On the other hand, keeping the temperature of the melt pool in an allowable range, which is dominated by the applied process parameters sets, and preventing temperature fluctuations impress the stability of the production and therefore the quality of the final product. The paper presents a multiphysics numerical model approach for obtaining parameters in an SLM process by using AlSi10Mg powders as the material medium. The proposed approach provides mathematical relationships between the process parameters and the temperature they form. By investigating the effect of laser power and laser spot diameter on the temperature at different scanning velocities, wider process parameter sets were obtained for AlSi10Mg. In addition, mathematical relationships between laser power-temperature and laser spot diameter-temperature at different scanning velocities, which will be the base material to design a controller to control the melt pool temperature instantly, were developed. By using the parameter sets obtained from the simulations, test samples including samples for microstructure study and tensile test specimens were fabricated to validate the model. The un-melted powders and nonconnected melt pool defects due to insufficient temperature, evaporation defects caused by extreme temperature, and appropriate and homogeneous microstructures as a result of suitable parameters that were predicted through simulations, affecting microstructure and mechanical properties, validated the model. The experimental study was carried out by examining the microstructure and tensile properties of the fabricated test samples.