Investigating the effect of defects on the crack initiation of additively manufactured IN718 using crystal plasticity simulations

Abstract

This study aims to analyze the effect of defects location on the fatigue behavior of additively manufactured IN718. A competing mechanism exists between persistent slip bands (PSBs) and volumetric defects on the initiation of fatigue cracks in AM IN718 under cyclic loading. Crystal plasticity simulations were performed to reveal the relative importance in crack initiation due to defects and PSBs. Cyclic loading was applied on a defect laden polycrystalline aggregate and the defect locations were systematically varied. The crack nucleation cycles and locations were captured using a strain contrast-based crack initiation criterion. The findings suggest that the presence of large defects affects the cyclic strain localization and crack initiation behavior of the AM IN718 material.