Investigating cause of the dissimilar ductility of Inconel 718 fabricated by electron beam melting (EBM)

Abstract

Additive manufacturing has become mainstream many areas. In recent years, aviation has been one of the leading industries using additive manufacturing. While generally metal materials are used in this sector, the production of metal materials with additive manufacturing can be in different ways. Electron beam melting(EBM) method is based on the powder bed fusion(PBF) principle. Thanks to the PBF, it is possible to produce parts that are difficult to produce by traditional methods. In this study, it is aimed to explain the different ductility behavior of IN718 produced by EBM method by phase analysis. When all the tensile test results are examined, it is seen that the final tensile strength and yield strength results decreased by about 3%, the area reduction was reduced by about 65%, and the decrease between the elongation results after fracture was 85%. The fracture surfaces were examined different phase images were seen in the samples with value of low ductility. To understand this difference, fracture surfaces and shiny surfaces were examined with electron microscopy and XRD. As a result of the examination, differences were observed in the areas with high Nb content and in the amount of a precipitate phase in the structure.