Thermal post-processing of AlSi10Mg parts produced by Selective Laser Melting using recycled powder

The performance enhancement of parts produced using Selective Laser Melting (SLM) is an important goal for various industrial applications. In order to achieve this goal, obtaining a homogeneous microstructure and eliminating material defects within the fabricated parts are important research issues. The objective of this experimental study is to evaluate the effect of thermal post-processing of AlSi10Mg parts, using recycled powder, with the aim of improving the microstructure homogeneity of the as-built parts. This work is essential for the cost-effective additive manufacturing (AM) of metal optics and optomechanical systems. To achieve this goal, a full characterization of fresh and recycled powder was performed, in addition to a microstructure assessment of the as-built fabricated samples. Annealing, solution heat treatment (SHT) and T6 heat treatment (T6 HT) were applied under different processing conditions. The results demonstrated an improvement in microstructure homogeneity after thermal post-processing under specific conditions of SHT and T6 HT. A micro-hardness map was developed to assist in the selection of the optimized post-processing parameters in order to satisfy the design requirements of the part.