High Cycle Fatigue of Additively Manufactured Inconel 625

Abstract

This research aims to investigate the influence of the microstructure, defect features, and surface roughness on the high cycle fatigue (HCF) strength of IN625 manufactured using L-PBF (Laser Powder Based Fusion) additive manufacturing (AM) process. 11 AM builds each containing several fatigue test specimens with axis of specimen oriented in either the z-direction (build direction) or transverse direction were manufactured to explore the influence of variations in laser scan speed, hatch spacing, and L-PBF machine system. Visual and SEM inspection of fractures was carried out to understand the nucleation mechanisms behind failure of these specimens. Finally, roughness tests were used to measure average roughness of specimens to find correlations with HCF performance.