Effects of Process Parameters and Heat Treatment on the Microstructure and Mechanical Properties of Selective Laser Melted Inconel 718

In this study, Inconel 718 superalloy was fabricated by selective laser melting (SLM) and solution treated at 980-1230 ℃subsequently. The process window was firstly set up based on the density of the samples. Samples were fabricated using various parameters within the process window to investigate the effects of process parameters on microstructure and mechanical properties. The average dendrite arm spacing and the volume fraction of Laves phase raise along with the increasing energy input. However, no distinct difference of tensile properties was found under parameters in the process window. Interdendritic Laves phase decreases with the solution temperature, while the grain size has the opposite trend. Finally, the solution temperature was fixed at 1080 ℃to dissolve Laves phases and obtain fine grains. After solution + aging heat treatment, the tensile strengths and ductility all exceed the wrought Inconel 718.