Emerging of high entropy alloy reinforced composites radiation shielding materials: Configurational structure and radiation shielding properties

In this study, equimolar high entropy FeCoNiCrNb nanocrystal material was added to 2024 quality aluminum alloy with powder metallurgy technique at 2 %, 4 %, 8 %, 16 %, 32 % and 64 % weight ratios to obtain nanocomposite structures. The microstructures of the obtained composite samples were examined by SEM imaging, elemental distributions by EDS analysis and phase structures by XRD analysis techniques. Then, in order to examine the radiation shielding feature, measurements were carried out with HPGe detector using 241Am, 133Ba, 57Co, 137Cs, 54Mn, and 60Co point sources with gamma energy in the energy range of 59.5 keV-1332.5 keV. In the final stage of the study, a series of mechanical property assessments were conducted on the nanocomposite structures, including hardness measurements, compressive strength tests and abrasive wear tests. In SEM examinations, it was observed that there was homogeneity in the surface grain distribution and the homogeneity gradually improved with the increase in the FeCoNiCrNb reinforcement ratio. However, it was determined that the increasing reinforcement amount caused agglomeration in places. The chemical presence of main matrix aluminum and high entropy reinforcement elements was determined by EDAX analysis. From the XRD analyses of composite structures, it has been determined that the Al phase is the dominant phase within the structure, the HEA alloy maintains its stability, and no interphase has formed between the HEA alloy and the main matrix. According to the linear attenuation coefficient, radiation protection efficiency, mean free path, and half value layer data obtained from this experimental study, it was concluded that the high entropy FeCoNiCrNb material provides a large amount of gamma-ray radiation shielding property, especially in the low energy region (92 % shielding efficiency at 59.5 keV, 76 % at 81 keV). Additionally, it has been determined that the hardness, compressive strength and abrasive wear resistance of composite structures are increased with the addition of high entropy FeCoNiCrNb.