Abstract

Additive manufacturing (AM) of metals has emerged as a transformative manufacturing technology capable of producing complex geometries, reducing material waste, and enabling unprecedented design flexibility across diverse industrial sectors. Over the past decade, significant advancements in metal AM processes have accelerated their adoption in aerospace, biomedical, automotive, energy, and defense applications. This review provides a comprehensive assessment of recent developments in metal additive manufacturing, with particular emphasis on processing technologies, microstructure evolution, and mechanical performance. Key metal AM techniques, including Powder Bed Fusion, Directed Energy Deposition, and Binder Jetting, are examined with respect to their operating principles, advantages, limitations, and process optimization strategies. The review further explores the complex thermal cycles and rapid solidification phenomena that govern microstructural characteristics such as grain morphology, phase composition, texture development, and defect formation. The influence of these microstructural features on mechanical properties, including strength, hardness, ductility, fatigue resistance, wear behavior, and corrosion performance, is critically evaluated. Recent advances in process monitoring, in-situ sensing, computational modeling, and artificial intelligence-driven optimization are also discussed as emerging approaches for enhancing part quality and manufacturing reliability. Furthermore, current challenges related to residual stresses, anisotropy, porosity, standardization, and large-scale industrial implementation are highlighted. By integrating findings from recent literature, this review provides a comprehensive understanding of the relationships between manufacturing processes, microstructural evolution, and mechanical behavior, while identifying future research directions that will support the broader industrial adoption and advancement of metal additive manufacturing technologies.