Investigation of the IN-738 superalloy microstructure and mechanical properties for the manufacturing of gas turbine engine nozzle guide vane by selective laser melting

Recently, there has been a significant amount of interest in additive manufacturing of aerospace parts from heat-resistant alloys due to the ability of producing more complex shapes parts in comparison with conventional technologies. This paper describes the research results of selective laser melting (SLM) of nickel-based IN-738 superalloy powder. The main research results of studies are microstructure investigation after SLM, hot isostatic pressing (HIP), and heat treatment on the cylindrical samples. The article presents results of short-term strength tests of cylindrical specimens at room temperature and 900 °C, and long-term strength. The research studies the influence of HIP on stress-strain behavior of specimens, which are built at different angles: 0, 45, 90°. The tensile strength of vertical samples is increasing by 60 MPa, at 45° is decreasing by 75 MPa, and at 0° is increasing by 139 MPa compared with the initial state. The developing IN-738 selective laser melting technology is approving by fabrication of GTE nozzle guide vane.