Long fatigue crack propagation behavior of Inconel 625 processed by laser powder bed fusion: Influence of build orientation and post-processing conditions

In this paper, the room temperature fatigue crack propagation behavior of Inconel 625 alloy processed by laser powder bed fusion was studied and compared to that of a wrought alloy of the same composition. First, the processing-induced defects distribution and the build orientation-dependent tensile properties of the laser powder bed-processed specimens were analysed. Next, crack propagation testing specimens were manufactured with four build orientations, half were subjected to stress relief annealing, while the other half were subjected to stress relief annealing followed by hot isostatic pressing. The impact of the build orientation and the post-processing conditions on the long fatigue crack propagation behavior at low R ratio (R = 0.1) was evaluated. The resistance to crack propagation of the laser powder bed-processed IN625 specimens was found to be similar to that of a wrought alloy.