|About this Abstract
||2021 TMS Annual Meeting & Exhibition
||Additive Manufacturing Fatigue and Fracture V: Processing-Structure-Property Investigations and Application to Qualification
||Using Post Build Porosity Analysis to Inform Future Build Strategies
||Connor Varney, Robert Quammen, Nicholas Telesz, John Balk, Andrew Wessman, Paul F. Rottmann
|On-Site Speaker (Planned)
Current percent-porosity based approaches seek to quantify the part-average porosity of an additive build. However, fatigue crack initiation and propagation is governed by local microstructure, which can be dominated by internal and surface defects. The size, shape, and distribution of internal defects strongly correlates to local solidification conditions which are build strategy dependent. In an effort to quantify such effects, sections of electron beam melted Ti-64 sample rods were imaged using optical microscopy to characterize the distribution and type (i.e. lenticular, spherical) of pores across the build. This analysis revealed a high concentration of lenticular (crack-like) pores within the contour-hatching boundary, suggesting a suboptimal delivered energy. Lenticular pores also appeared at a substantially higher rate (>60x) on fatigue crack surfaces, suggesting that lenticular pores are more deleterious than spherical pores to the part’s mechanical reliability. Given their differing formation mechanisms, this knowledge could be used to inform future build strategies.