Effects of furnace temperature of stress-relief annealing on residual stress and hardness characteristics of heterogeneous materials fabricated from a DED process

The residual stress causes a premature failure of the manufactured product by a directed energy deposition (DED) process. The stress-relief annealing process can effectively decrease the residual stress. However, the research on the stress-relief annealing on residual stress characteristics of the fabricated part by the DED process consisting of heterogeneous materials has hardly performed yet. The goal of this research work is to investigate the effects of the furnace temperature of stress-relief annealing on residual stress and hardness characteristics of heterogeneous materials fabricated from the DED process. The as-built specimen was created by the deposition of Gridur 6 (G6) powders on AISI 1045 substrates using the DED head of DVF-8000AML. The stress-relief annealing process of the as-built specimen was carried out using an electric furnace. The influence of the furnace temperature on the surface morphology, the residual stress of the boundary region and the hardness of top and bottom surfaces was discussed. Finally, proper furnace temperatures of the stress-relief annealing were proposed.