Identification of strain localization and fracture behavior of additive manufactured metallic lattices using digital image correlation: Effects of strain direction

The digital image correlation (DIC) technique has been applied to identifying the fracture mechanisms of additive manufactured metallic lattices. However, the strain distribution obtained by DIC is generally analyzed along the loading direction. In this study, the effects of strain direction on the deformation and fracture behaviors of selective laser melted (SLM) CuZrAl metallic glass lattices and Corrax maraging stainless steel lattices were examined and discussed. The results show that in SLM CuZrAl lattices, the strain localization and fracture were dominated by the strain along the lateral direction (epsilon xx). In contrast, the strain along the compression direction (epsilon zz) controlled the deformation and fracture modes of the SLM Corrax lattices. The above trend can be attributed to the differences in the compressive ductilities of the two types of SLM metallic lattices. The compressive ductility of SLM CuZrAl lattices was low, and thus they could not withstand the tensile loading along the lateral direction during the compression test. These findings provide valuable information about the application of DIC by identifying and explaining the fracture mechanisms of a structural material.