Influence of SLM Processing Parameters on Intrinsic Defects and Mechanical Properties

Selective Laser Melting (SLM) is an advanced 3D printing technology for producing metallic components, offering design versatility, near-net-shape manufacturing, and potential for material efficiency. Despite these advantages, the process is inherently linked to defect formation, such as gas pores, lack of fusion zones, impurities, and issues associated with the keyhole phenomenon. These defects can significantly affect the material’s mechanical integrity, especially its fatigue performance. This study investigates how different SLM processing parameters influence defect generation and their impact on mechanical properties and, consequently, on structural integrity. To accomplish this, a wide range of characterisation techniques, such as nanotomography, scanning electron microscopy (SEM), optical microscopy, and microhardness measurements, were employed to examine both surface and internal features of the components, thereby detecting and assessing the type, size, and distribution of defects. This research additionally explores the potential impact of metallic powder reuse on defect formation and material behaviour, contributing to the discussion on sustainable practices in additive manufacturing. The results provide valuable insights into optimising SLM parameters to reduce internal defects and support more sustainable production strategies.