Plastic Deformation Behavior in the Dynamic High Strain Rate of Additively Manufactured AlSi10Mg

Laser powder bed fusion (L-PBF) has emerged as a prominent additive manufacturing technology for producing lightweight aluminum alloy components with complex geometries. The layer-based fabrication process introduces orientation-dependent microstructural characteristics that significantly influence mechanical performance. In this study, the plastic deformation behavior of L-PBF-fabricated AlSi10Mg alloy was investigated for two build orientations: vertical and horizontal. The crystallographic structure and lattice characteristics were examined using X-ray diffraction (XRD). The microstructural parameters, including crystallite size and micro-strain, were evaluated through the Williamson–Hall method. Dynamic plastic deformation behavior was assessed under high strain-rate loading using a split Hopkinson pressure bar (SHPB) apparatus. We found that the results revealed a strong dependence of crystal structure, residual micro-strain, and lattice deformation energy on build orientation. This indicates the presence of anisotropic microstructural features induced by the additive manufacturing process. We also observed a significant difference in lattice micro deformation between the vertically and horizontally built specimens, leading to variations in their deformation response under dynamic loading. Furthermore, we found a positive correlation between lattice deformation energy and maximum flow stress for both build orientations. Specimens exhibiting higher lattice deformation energy demonstrated enhanced resistance to plastic flow and consequently attained greater flow stress during high strain-rate deformation. These findings provide valuable insights into the structure–property relationships governing the dynamic mechanical behavior of additively manufactured AlSi10Mg alloys and contribute to the optimization of orientation-dependent performance in engineering applications.