Analytical Methods to Understand Deformation Mechanics in Additively Manufactured Metals

Additively manufactured metals can show more than an order of magnitude increase in variability in mechanical properties compared to traditionally manufactured materials. This makes the qualification of additively manufactured parts difficult, especially in safety critical applications where unexpected material failure can be detrimental. Sandia has been leading multiple efforts to understand the nature of this stochastic behavior by developing methodologies to efficiently characterize the variability in nominally identical parts, and investigating the role that stochastic defects, primarily voids, play in the deformation and fracture of components. In this talk we discuss the development of an automated high-throughput tensile testing set-up, utilized in a preliminary processing parameter study. We next discuss several studies that were motivated by this work where we utilized in situ micro-computed tomography to characterize the evolution of part geometry and void morphology in both simple and complex geometries, identifying the deformation mechanisms associated with void networks. Overall, these works have led to improvements in understanding the nature of stochasticity in additively manufactured metals and advancing our capabilities to predict and model failure in these materials.