Welding and Joining of Metallic Materials

This Special Issue, "Welding and Joining of Metallic Materials: Microstructure and Mechanical Properties, 2nd Edition," presents a collection of ten high-impact research articles that advance the frontiers of metallurgical joining technologies. The volume addresses a critical engineering challenge: the optimization of the interface between complex microstructural evolution and the resulting mechanical performance of welded joints. This Reprint is organized into three strategic domains. First, it explores innovations in arc welding through the development of activating fluxes and nanostructured functional ceramic coatings for electrodes, significantly enhancing penetration depth and arc stability. Second, it highlights the integration of computational intelligence, using methods such as Particle Swarm Optimization (PSO) and Response Surface Methodology (RSM) to predict and refine weld geometries. Finally, this collection investigates specialized dynamics in solid-state joining and high-energy density processes, including Friction Stir Spot Welding and Variable Polarity Plasma Arc dynamics. By bridging the gap between theoretical modeling and robust experimental validation, this collection provides actionable insights for the automotive, aerospace, and energy sectors. It serves as an essential reference for engineers and researchers seeking to enhance the structural integrity, efficiency, and longevity of metallic components in rigorous industrial environments.