Dual-effect of Holmium(III) oxide and Boron Carbide reinforcement on physical, microstructural evolution and gamma-ray shielding performance of 316L-SS

This study provides one of the first comprehensive evaluations of 316L stainless steel composites reinforced with 10 wt.% B 4 C and varying concentrations of Ho 2 O 3 , proposing a new compositional design for simultaneous structural enhancement and dual gamma-neutron shielding optimization. XRD analysis confirmed the predominance of the austenitic phase with minor martensitic peaks at higher Ho 2 O 3 levels. SEM and EDX results revealed uniform dispersion and improved densification with increasing oxide content. The 316L-B 4 C-20%Ho 2 O 3 composite exhibited the highest mass attenuation coefficient (0.8953 cm 2 /g) and linear attenuation coefficient (6.73 cm −1 ) at 0.1 MeV, demonstrating superior gamma-ray shielding capability. The effective electron density increased from 2.86 × 10 23 to 5.82 × 10 23 electrons/cm³, while the energy absorption buildup factor (EABF) showed a consistent decrease with higher oxide concentrations. Although a slight reduction in fast neutron removal cross-section was observed, the composite maintained satisfactory neutron attenuation performance. Overall, the findings indicate that the 316L-B 4 C-20%Ho 2 O 3 system offers a promising balance between structural stability and dual radiation protection, making it a strong candidate for next-generation nuclear shielding materials.