In situ X-ray micro-computed tomography study of the damage evolution of prefabricated through-holes in SLM-Printed AlSi10Mg alloy under tension

Drilling holes used to mechanically connect complex structures would affect the residual stress of metal alloys, resulting in delamination of selective laser melting (SLM)printed bulk samples. These limitations could be overcome by the pre-fabrication of through-holes during SLM processing using computer-aided design (CAD) models with holes. However, thus far, there has been rarely study discussing the impact of pre-fabricated through-holes on damage evolution and failure mechanisms of SLM-manufactured structures under quasi-static tension. In this study, damage evolution in SLM-printed AlSi10Mg alloys with two prefabricated through-holes was investigated. In situ X-ray tomography tensile tests were performed to evaluate the morphology, location, and distribution of geometric imperfections and to clarify their role in the mechanical response of samples under quasi-static tension. To numerically reproduce the experiments at the meso-scale, an image-based finite element model (FEM) was constructed from 3D images and the results were compared to those obtained by ideal CAD model simulation. In addition, damage evolution of geometric defects was extracted from the FEM and experimental results. The geometric defects increased the in-plane shear stress remarkably and resulted in the crack propagation in AlSi10Mg alloys. It was shown that the mechanical response of AlSi10Mg bulk samples was linked to the initial morphological features of through-holes. This comprehensive combined geometric morphology of defects and the mechanical response will serve to complete the dimensional compensation design and replacement of secondary drilling holes in additive manufacturing technology in future studies.