Heat Treatments Of Inconel 718 Produce By L-DED

Inconel 718 (INC718) components manufactured by Directed Energy Deposition (DED) require optimized post-processing heat treatments due to their distinct solidification conditions and resultant microstructures compared to conventional manufacturing methods. While extensive research exists on heat treatments for wrought and powder bed fusion-produced INC718, limited studies address DED-specific heat treatment optimisation. This study and explores the effects of various solutions and ageing heat treatments on DED-manufactured INC718 through samples' mechanical and microstructural characterisation by using OM, SEM|EDS|EBSD, and Vickers hardness testing. The as-deposited material exhibited significant niobium segregation and Laves phase formation in interdendritic regions. Solution treatment at 1150°C proved more effective at dissolving Laves phase compared to conventional 980°C treatment. Modified solution and ageing parameters (1150°C|1h + 720°C|8h + 620°C|8h) resulted in significantly improved hardness (491±13 HV0.2) compared to standard heat treatments. These findings demonstrate the necessity of developing specific heat treatment protocols for DED-manufactured INC718 to achieve optimal properties.