Stabilization of metal structure formation in directed energy deposition by applying a coolant system

Directed energy deposition (DED), which is one of additive manufacturing processes applicable to metals, is suitable to produce a large-scale complex-shaped part in aerospace and automobile industries. However, mechanical characteristics in a DED-produced part often varies according to the thermal conduction at each deposition point. To ensure quality uniformity in a DED-produced part, a cooling process also should be actively performed to control the thermal condition. This study evaluates variation in crystal structure in parts produced with DED applying a coolant system. By performing the cooling process at certain intervals during deposition, the variations in Vickers hardness and crystal structure are effectively suppressed in DED of Inconel 625.