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Abstract:
Present investigation systematically quantifies the role of interior defect morphology on tensile fracture behavior in Binder Jetting Additive Manufactured (BJAM) 17-4 PH stainless steel. Unlike prior investigations relying on stochastic natural defects, BJAM is uniquely employed to fabricate tensile specimens with five precisely controlled interior defect geometries such as spherical, disc-shaped, ellipsoidal, inclined ellipsoidal, and two-spherical at the mid-gauge location of round and square cross-sectional configurations. These artificial defects, occupying 16–35% of the gross cross-sectional area, serve as morphologically defined analogues of shrinkage porosities typical of conventional steel castings. A novel shape-independent empirical net section yielding method is developed that directly correlates projected defect area to fracture stress across all five defect geometries and both cross-sectional configurations. Results demonstrate that tensile strength reduction is governed by projected defect area independent of defect shape, with predictions falling within ±10% for the majority of configurations, providing a practically applicable fracture stress prediction tool for defect containing BJAM components. 3D finite element simulations coupled with a ductile damage model are implemented to accurately predict crack initiation sites and experimental load–displacement responses, achieving excellent agreement with experimental findings and providing independent computational validation of the empirical framework.

Keywords:
Binder jetting additive manufacturing, Ductile damage model, Interior defects, Shrinkage porosity, 17-4PH steel