In situ fabrication and characterization of Al-Si/Al2O3 composites via powder metallurgy for Neutron shielding applications

Neutrons play a vital role in nuclear energy systems, medical treatments such as neutron radiotherapy and radioisotope production, neutron activation analysis, defense technologies, aerospace, and scientific research. However, their high penetration depth often leads to radiation leakage, creating a need for lightweight and durable shielding materials. In this study, four Al-Si-Al2O3 composites were fabricated using aluminum (Al), silicon (Si), and silicon dioxide (SiO2) powders by powder metallurgy and subsequently sintered at 640 degrees C. Structural and mechanical properties were assessed by Brinell hardness, density, porosity, wear resistance, and Xray diffraction analyses. The composites demonstrated hardness values nearly ten times higher than pure Al, while Scanning Electron Microscopy confirmed in situ Al2O3 formation and the uniform distribution of Al and Si. Neutron shielding properties, including effective removal cross section, neutron transmission ratio, half-value layer, mean free path, and radiation protection efficiency, were evaluated using GEANT4 Monte Carlo simulations. Experimental dose measurements were performed with a241Am-Be fast neutron source and a BF3 detector. Results showed that all composites had significant neutron attenuation capabilities compared with 316LN stainless steel. These findings highlight Al-Si-Al2O3 composites as promising lightweight alternatives for neutron shielding in nuclear, aerospace, and defense applications.