Abstract:Selective laser melting (SLM) is a laser cladding/deposition based technology, which can fabricate and repair near-net-shape high-performance components directly from metal powders. Characterizing mechanical properties of the SLM components is prerequisite to the applications of SLM in aircraft engine industrial productions. Nickel-based superalloys such as IN718 are the most commonly used metal materials in aircraft engine high-performance components. In the present study pre-alloyed, rapidly solidified IN718 powder served as a precursor for the production of additive manufactured components using SLM. The laser deposition process is optimized through a set of designed experiments to reduce the porosity. Material microstructure and mechanical properties of laser-deposited IN718 are studied and compared under heat treatment conditions of as deposited, direct aged, solution treatment and aging (STA), and full homogenization followed by STA. Tensile test results showed that the direct age treatment produces the highest tensile strength to the wrought material, while the homogenization treatment followed by STA exhibits good ductility. Failure modes of the tensile samples were analyzed by fractography. Considering the room and high temperature tensile test results of three heat treatment, homogenized STA samples not only have higher strength than the AMS wrought specifications, but also have good plastic. Therefore, homogenized STA is suitable heat treatment method for LSM IN718 alloy. Then, stress rupture properties at 650 oC/700 and 725 MPa, low cycle fatigue properties at 455 oC of the homogenized STA samples were investigated, fracture mode was analyzed and compared to wrought IN718 alloy.