Influence of energy density on metallurgy and properties in metal additive manufacturing

Fabricating metallic components for highly specialised industries such as automotive and aerospace has become the main focus of additive manufacturing (AM) due to its many advantages over traditional processes. This review initially outlines current AM techniques for processing metallic components, particularly on 'powder bed fusion' and 'directed energy deposition' categories. Various solidification and metallurgical aspects, microstructure and properties of fabricated parts are described in subsequent sections. In addition, the influence of energy density on metallurgy, microstructure and mechanical properties is addressed. The need to establish processing maps for various materials and techniques, and the challenges currently faced in metal AM are then highlighted. The final section provides an outlook for the future of research in AM of metals.