Recent insights into morphology evolutions during 3D printing processes of advanced materials

Three-dimensional (3D) printing technologies have attracted significant interest from both academia and industry because of their extraordinary power and merits in manufacturing products over traditional manufacturing techniques. They are particularly well suited for the fabrication of complex 3D structures. Over the past two decades, substantial research and development efforts have led to remarkable advances in these technologies. Nevertheless, significant challenges remain, particularly in establishing comprehensive and reliable databases that capture the evolution of morphological structures during the printing process. Such structures include hierarchical features across multiple length scales and orientations, dimensional accuracy, and surface quality. These data are essential for optimizing processing conditions, understanding structure–property relationships, improving property performances, and expanding the global additive manufacturing market. Real-time approaches for monitoring morphological evolution during 3D printing have been demonstrated; however, their implementation remains at an early and relatively limited stage. In-situ scattering techniques enable probing of hierarchical structures from atomic to micrometer length scales, while real-time microscopy methods provide complementary information on porosity, geometry, and material dynamics during fabrication. To date, however, these studies have focused on a narrow range of materials and have largely relied on basic or qualitative analyses. This highlights the need for broader adoption of such techniques and for more rigorous, quantitative data analysis to establish robust correlations among processing parameters, structural evolution, and resulting material properties. This article reviews real-time morphology analysis techniques that have been implemented or are under development for 3D printing technologies, along with the analytical outputs they generate. It also discusses perspectives on future advances in in-situ monitoring of morphological evolution across all areas of additive manufacturing.