ABSTRACT
Direct Metal Deposition (DMD) is a laser-aided Additive Manufacturing (AM) technology in which metallic materials and structures are created by deposition of metal powder through a moving nozzle and melting of these powders through a co-axial laser beam in the nozzle (Mazumder et al. 2000; Imran et al. 2011). Rapid solidification of metal melt pool enveloped by an inert gas creates the layers on a substrate according to the computer aided design data. The DMD system is equipped with sensitive closed loop feedback control which provides information for the computerized system on the process and the layer being deposited. Figure 1 shows the schematic of the DMD process (Soodi et al. 2014). As-deposited material in this process is fully dense and the mechanical and physical properties of the fabricated parts can be as good as or better than those of comparable cast or wrought materials. DMD materials can be fully stress relieved, heattreated, and aged to alter the microstructures for specific applications and to improve ductility or toughness. DMD has also been successfully applied in a wide range of materials including stainless steel, tool steel, Ni-alloys, Co-alloys, Ti-alloys, and refractory material such as cermet.
