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Additively manufactured metals often contain pores, which limit the strength and ductility of resulting components. In this study, a ductile fracture model was developed to describe the effect of pore size, in terms of absolute and relative metrics, on fracture strain under uniaxial tension. The model approximates lack of fusion (LoF) pores as penny-shaped cracks, and damage accumulation was based on the J-integral and secondary Q parameter. The model was calibrated with Ti-6Al-4V samples with intentionally introduced pores fabricated by laser powder bed fusion (PBF-LB) additive manufacturing (AM) in as-built and heat-treated conditions. The model captures the experimentally observed size effect, where for a given pore area fraction, larger samples fracture at smaller strains. By identifying the critical pore size for a single, isolated pore for either load or displacement-controlled applications, the model developed in this study is a crucial step to developing a comprehensive fracture model for establishing confidence in the structural capability of pore-containing additively manufactured components.
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This content will become publicly available on July 1, 2026
Identifying fracture location in additively manufactured samples based on defect characteristics: Demonstration using AlSi10Mg
A new metric was developed to quantify the impact of surface-connected defects and internal pores of different morphologies, namely irregular lack of fusion (LoF) pores and spherical keyhole pores, on the mechanical properties and fracture location of AlSi10Mg tensile samples fabricated using laser powder bed fusion additive manufacturing. As defect volume alone has been shown to be insufficient to predict fracture location, the proposed defect impact metric (DIM) incorporates contributions from additional defect features, including proximity to the surface, interaction with neighboring defects, morphology, and reduction in load-bearing cross-sectional area to better assess a defect’s propensity for corresponding to fracture location. The fracture location of keyhole samples was captured by large surface-connected defects with numerous neighboring defects and resulted in increased losses in load-bearing area. In contrast, LoF samples fractured at regions with either large surface-connected defects or large internal pores with many defects in close proximity, high curvatures, and large projected areas. The proposed DIM outperformed existing defect-based frameworks in identifying fracture locations in both LoF and keyhole samples by incorporating surface roughness, defect projected area, and interactions between defects based on distance, volume, and configuration. Additionally, the maximum DIM value within the fracture range was more strongly correlated to strength and ductility than porosity or defect size for LoF samples, demonstrating the potential of the DIM to non-destructively assess the effects of defects on mechanical behavior. The broader applicability of the DIM framework was demonstrated in its ability to capture fracture in both PBF-LB AlSi10Mg and Alloy 718.
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- Award ID(s):
- 1652575
- PAR ID:
- 10636156
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Additive Manufacturing
- Volume:
- 110
- Issue:
- C
- ISSN:
- 2214-8604
- Page Range / eLocation ID:
- 104935
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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