Gamma shielding behavior of Al-Cr-Mo-Ta-Ti HEAs with varying Al/Ta ratios: Comparative calculations via WinXCOM,...

In the present study, the influence of the Al/Ta ratio on the gamma-ray shielding performance of an Al-Cr-Mo-Ta-Ti-based HEA system was investigated through theoretical calculations. The mass attenuation coefficients (μ_ρ, cm²g^-1) for six distinct compositions (HEA1-HEA6) were computed over the energy range of 0.03-15 MeV using WinXCOM, EpiXS, Phy-X/PSD, and Py-MLBUF software, with results demonstrating a high degree of agreement across the employed computational approaches. Additional radiation shielding parameters, including the half-value layer (HVL, cm), mean free path (mfp, cm), effective atomic number (Z_eff), electron density (N_el), and buildup factors (EBF and EABF), were evaluated using the EpiXS program. The results revealed that increasing Ta content led to an increase in alloy density (6.55-8.95 g/cm³), which corresponded to a decrease in HVL and MFP values. At lower photon energies, the dominance of the photoelectric effect caused an increase in μ/ρ values, whereas pronounced K-edge absorption features were observed in compositions with higher Ta content. Specifically, the HEA6 sample exhibited a μ_ρ value of 4.325 cm²/g at 81 keV, indicating superior gamma-ray attenuation capability compared to many conventional shielding materials reported in the literature. Overall, the findings indicate that Al-Cr-Mo-Ta-Ti HEAs represent promising candidates for radiation shielding applications, providing an effective alternative to traditional materials in scenarios demanding enhanced gamma-ray attenuation.