| Abstract Scope |
Fatigue failure of certain additively manufactured (AM) materials in machined surface condition, such as Ti-6Al-4V, can almost always be traced back to one or a group of volumetric defects, including gas-entrapped pores, key holes, and lack-of-fusion defects. Their size, shape, and location can influence the initiation of fatigue cracks, which occupies a major portion of fatigue lives in the mid and high cycle fatigue regimes. For others, especially ones with coarser microstructure such as Inconel 718, the crack initiation is known to be less sensitive to the presence of defects. Therefore, the synergy between the features of volumetric defects and microstructure appears to dictate the fatigue behavior, especially high cycle fatigue, of these AM materials. This presentation provides a snapshot of current research efforts at the National Center for Additive Manufacturing Excellence (NCAME) on the understanding of such synergistic effects in laser beam powder bed fused alloys. |