Room Temperature Mechanical Properties of Additively Manufactured Ni-base Superalloys: A Comparative Study

The unique layer-by-layer manufacturing strategy and near-net shaping capability of Additive Manufacturing (AM) make it a promising technology for Ni-superalloys components, where their typical service conditions demand complex shapes and impose significant production costs due to the alloys' poor machinability. In this work, the room temperature mechanical behavior of several Ni-superalloys, including Hastelloy X, Inconel 718, and Inconel 625, were investigated and their properties/performances compared. The test specimens were produced using various AM processes such as laser powder bed fusion (L-PBF) and/or laser powder direct energy deposition (LP-DED). Thorough analyses on microstructures as well as mechanical performance under static/cyclic axial loads have been performed on test specimens. This study aimed to provide a better understanding of process-structure-property relationship for the AM processed Ni-superalloys in two steps. In the process-structure step: the microstructural evolution as the result of thermal cycles has been studied by quantitative metallography based on scanning electron microscopy (SEM). In the structure-property step: both measured fatigue and tensile properties were attempted to be correlated with microstructure. (C) 2021 The Authors. Published by Elsevier B.V.