Jaafar El-Awady1,Markus Sudmanns1,Andrew Birnbaum2,Yejun Gu1,Athanasios Iliopoulos2,Patrick Callahan2,John Michopoulos2
Johns Hopkins University1,United States Naval Research Laboratory2
Jaafar El-Awady1,Markus Sudmanns1,Andrew Birnbaum2,Yejun Gu1,Athanasios Iliopoulos2,Patrick Callahan2,John Michopoulos2
Johns Hopkins University1,United States Naval Research Laboratory2
Additive manufacturing (AM) of metallic components promises many advantages over conventional manufacturing processes through high design flexibility across multiple length scales and precision coupled with an astonishing combination of mechanical properties. Characterizing the relationship between microstructure and mechanical properties of additively manufactured metals remains one of the major challenges. A natural precursor is identifying the influence of the processing path on the developing microstructure. We combine experimental studies of single-track laser powder bed fusion (LPBF) scans of 316L stainless steel, finite element analyses, and large-scale three-dimensional discrete dislocation dynamics simulations to provide a unique understanding of the underlying mechanisms leading to the formation of heterogeneous defect structures in additively manufactured metals. Our results show that the interruption of dislocation slip at solidification cell walls is responsible for the formation of cellular dislocation structures, highlighting the significance of solute segregation for plastic deformation of additively manufactured components. This work provides a mechanistic perspective on heterogeneous microstructure formation and opens the potential for a reliable prediction of the resulting mechanical properties of additively manufactured parts.