On the Criticality of Defect Features in Failure of Additively Manufactured Components

Porosity and other defects resultant by additive manufacturing processes are well-known to affect mechanical properties. However, there remains limited understanding regarding how the internal defect structure influences the evolution of the local strain field, as experimental investigations have not presented direct measurements of the evolving internal strain field in the presence of defects. Further, the criticality of specific defect characteristics on failure of additive manufacture components is not well understood. In this presentation, we will discuss results from interrupted in-situ tensile tests in X-ray computed tomography environments that were used to investigate the evolution of the strain field around internal defects via digital volume correlation. The evolution of the internal strain field facilitated examination of the role of specific defects in the macroscopic deformation of additive manufactured components. Characteristics of the porosity distribution, including presence of porosity at the surface or near-surface of components, as well as the local proximity of pores were found to influence the evolution of failure. Early onset of failure was found to be associated with the availability of neighboring porosity that allowed for rapid progression of the fracture path. Complementary to these high fidelity in situ evaluations of defect-driven failure, we also will detail similar results from statistical and machine learning based approaches from pre-mortem structure measurements that highlight the importance of similar defect characteristics in driving failure for additive manufactured components.