Additive manufacturing of nickel-based superalloy gas turbine components

The swirler of the gas turbine combustion chamber is usually designed from nickel-based superalloys and produced by the conventional precision casting method under vacuum. The production of such parts is associated with high scrap due to geometrical complexity, high dimensional accuracy and also the use of ceramic cores. In recent decades, the use of the additive manufacturing process as a new and alternative method has been growing for the production of complex metal parts in the power plant industry. In this research, a gas turbine Swirler and several Inconel 625 samples were fabricated by SLM in optimal conditions of the main variables of the manufacturing process such as laser power, scanning speed and the thickness of the melted layer. Microstructural studies were performed by optical Microscope on samples and some structural defects such as incomplete local melting, porosity, non-metallic oxide phases and Microcracks were identified. The printed swirler was compared with the computer model in all important and final Surfaces by non-contact dimensioning method. The surface quality and dimensional accuracy of the part were acceptable and it was evaluated within the tolerance range of the casting part. Also, hardness and tensile tests at ambient temperature were performed on the heat treated samples. The results showed that the values of the tensile properties of the printed samples were higher in the parameters of yield strength and ultimate strength, but lower in the parameter of relative elongation and the hardness was also the same.