Abstract
Directed Energy Deposition (DED), one of the metal additive manufacturing processes, can produce large-sized and complex-shaped parts using difficult-to-cut materials. From this aspect, DED starts to be used in airplane and turbine productions these days. DED is a process forming a melt pool on the deposition point by irradiating laser and supplying metal powder simultaneously. However, the cooling condition at deposition point drastically changes in DED because the exhaust heat depends on the shape and thermal property of deposit. Therefore, the quality of DED-produced part is difficult to keep stable because the bias of mechanical properties easily appears according to the deposition condition. In this research, the coolant supply system for DED was prepared, and the influence of temperature change on the mechanical properties was evaluated. Furthermore, a preferable cooling condition was experimentally identified to obtain a uniform mechanical property in the deposit through Vickers hardness measurement and metallurgical structure observation.
