Interplay of crystallographic orientation and density on gamma-ray shielding properties: A case study of the Al0.25CoCrFeNi high entropy alloy

This study investigates the interplay between crystallographic orientation and density on the γ-ray shielding properties of the Al0.25CoCrFeNi high entropy alloy (HEA). The mass attenuation coefficient (MAC) and linear attenuation coefficient (LAC) was evaluated for four crystallographic orientations-[100], [110], [111], and [110]-across a photon energy range from 0.015 MeV to 15 MeV. Results show a pronounced anisotropy in LAC values at low photon energies (0.015–0.050 MeV), with the [111] orientation exhibiting the highest LAC (58.23 cm−1 at 0.03 MeV), which corresponds to a density of 2.85 g/cm³ . In contrast, the [110] orientation showed the lowest LAC (55.65 cm−1 at 0.03 MeV), with a density of 2.72 g/cm³ . As photon energy increases, the difference in LAC values between orientations diminishes, with all orientations converging to approximately 0.080 cm−1 at 15 MeV, indicating that at high energies, the LAC values become largely independent of the crystallographic orientation. However, the MAC values are found to be independent of crystallographic orientation which ranged between 0.025 and 45.491 cm2/g for high and low energies respectively. This suggests that while crystallographic orientation plays a significant role in γ-ray attenuation at low energies, while its influence is less critical at higher photon energies, where density becomes the dominant factor. These findings highlight the potential for optimizing radiation shielding in HEAs by tailoring crystallographic orientation, particularly for applications involving low-energy radiation. [Display omitted] •Anisotropic gamma-ray shielding for LAC.•Anisotropic independent gamma-ray shielding for MAC.•Orientation independence at high energies for both LAC and MAC.•Optimizing shielding performance by tailoring crystallographic orientation and density in HEAs.