Tracking defects and microstructural heterogeneities in meso-scale tensile specimens excised from additively manufactured parts
Jake T. Benzing, Li-Anne Liew, Nikolas W. Hrabe, Frank W. DelRio
The commercialization of additive manufacturing (AM) is underway in the aerospace and biomedical device industries [1, 2]. However, most metal parts produced by AM are limited to non-critical applications, since the various processes produce internal porosity, anisotropy, and microstructural heterogeneities [1, 3]. It has been implied that small-scale mechanical tests can advance measurement standards for AM applications by probing the effects of defects and heterogeneities on mechanical properties at more appropriate length scales [4, 5]. Traditionally, small-scale techniques have been used to characterize location- and orientation-specific mechanical properties in wrought materials [6, 7, 8, 9, 10]. A common method for excising mechanical test specimens from bulk parts with negligible influence on specimen integrity involves electrical discharge machining (EDM) . This work demonstrates that excising meso-scale tensile specimens from additively manufactured parts enables tracking of sub-surface and visible features of interest (porosity and microstructural heterogeneities) throughout the entire gauge section such that the individual contributions to deformation behavior can be assessed.