MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AlSi10Mg PARTS PRODUCED BY THE LASER BEAM ADDITIVE MANUFACTURING (AM) TECHNOLOGY

Selective laser melting (SLM) is an additive manufacturing (AM) technique for fabrication of near net shape parts directly from computer-aided design data from a series of layers each one melted on top of the previous one by a laser beam. AlSi10Mg specimens were produced by the SLM technique from gas atomized pre-alloyed powders. This work reports results for AlSi10Mg powder properties assessment. The particle size, morphology, phase and chemical composition were characterized. The work also encompasses different metallurgical aspects of the AM process and tries to provide better insight to the correlation between the distinctive layered macrostructure, and the extremely fine cellular dendritic microstructure obtained by the SLM AM process, along with the remarkable tensile testing results for AlSi10Mg components. High thermal gradients determine the small eutectic colonies of the microstructure. Scanning electron microscopy revealed anisotropy of the parts, inherent to the AM-SLM process, dependent on the build orientation. It is shown that AlSi10Mg parts produced by SLM display room temperature mechanical properties comparable or even exceeding to those of conventionally cast AlSi10Mg. The hatching strategy is crucial for the layer by layer AM process and understanding the properties of components produced by this technique. We demonstrate the possibility to visualize the macrostructure of components fabricated by AM resulting from different building strategies. A comparison with actual built AlSi10Mg components provides a better understanding of the visualization model.