Optimization of the microstructural, mechanical, and radiation shielding properties of Al-30B4C-25 W hybrid composites with Gd2O3 reinforcement

In this study, Al-(30-X)B₄C-(X)Gd₂O₃-25 W (X = 5, 10, 15, 20, 25, and 30) hybrid composites were fabricated using high-energy ball milling. The composite powders were milled for 5 h and subsequently cold-pressed into cylindrical pellets under a pressure of 750 MPa. The mechanical, physical, and radiation shielding properties of the resulting pellets were systematically investigated. To prevent oxidation, the pellets were sealed under vacuum and sintered at 600 °C for 3 h in an argon atmosphere. X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) were employed to analyze the microstructure and phase composition of the composites. Furthermore, the relative density, hardness, corrosion resistance, and wear resistance were systematically investigated. High-energy ball milling was optimized to investigate the effects of Gd₂O₃ and B₄C ratios on the density, hardness, and corrosion behavior of the composites. The results show that the relative density value peaks at Al-30Gd₂O₃-25 W content, while the hardness and wear resistance values are maximized at Al-30B₄C-25 W content. Furthermore, the corrosion resistance improved significantly with increasing Gd₂O₃ content. This is attributed to the fact that Gd₂O₃ increases microstructural stability, preventing the formation of microcracks and forming a protective film on the surface. The MCNP simulation results reveal that incorporating Gd₂O₃ in place of B₄C enhances thermal neutron and gamma-ray shielding properties, while slightly reducing fast neutron shielding performance. These findings suggest that Al-B₄C-Gd₂O₃-W hybrid composites can be designed to optimize their mechanical, corrosion, and wear properties for various engineering applications. In particular, careful selection of process conditions and component ratios plays a critical role in enhancing the overall performance of these composites.