On the multi-scale mechanical and tribological behavior of directed energy deposited inconel-718

Inconel-718 superalloy was additive-manufactured via laser direct energy deposition, followed by distinct post-processing thermal treatment conditions. Nanoindentation mapping revealed that samples subjected to double aging exhibited the highest average hardness and elastic modulus, attributed to the precipitation of γ′ and γ″ phases during the double-aging heat treatment. The presence of these precipitates was confirmed, resulting in tensile strength levels exceeding 1350 MPa along with improved wear resistance. However, direct double-aged condition showed lower elongation, attributed to the formation of brittle phases. Wear experiments further demonstrated the effectiveness of thermal processing in enhancing overall mechanical and tribological performance compared with the as-built condition.