Influence of powder characteristics on microstructure and mechanical properties of Inconel 718 superalloy manufactured by direct energy deposition

This work reports a study of the differences between properties of gas atomized (GA) and plasma rotating electrode processed (PREP) Inconel 718 powder and their printed parts. Powder morphology, particle size distribution, chemical composition, flowability and density have been comprehensively analyzed. From that, it can be found the properties of PREP powder were better than GA powder. The densification, microstructure, mechanical properties, and oxidation resistance of GA and PREP samples prepared by direct energy deposition(DED) were also studied. The results showed that the perfect morphology of powder could contribute to a finer microstruture and a more obvious preferential orientation of the printed part. Moreover, the density, mechanical properties and oxidation resistance of the printed parts were all better. This work highlights that properties of powder are crucial to the properties of the printed parts, and emphasises the importance of powder morphology on energy absorption, microstructure and preferential orientation in DED process.