Search

In this study, boralyn (boron carbide-aluminum metal matrix composite material — Al/B4C) composite materials were investigated on shielding effect against gamma and neutron radiations. The samples were prepared as 5 wt%, 10 wt%, 15 wt%, and 20 wt% reinforcement content and for each content of material has composed in five different average particle sized (3 μm, 53 μm, 113 μm, 200 μm, and 500 μm). Linear and mass attenuation coefficients were calculated experimentally for each composite material against Cs-137 gamma source. Theoretical mass attenuation coefficients of material were calculated by using XCOM computer code. Then the theoretical results were compared with experimental results. Then, macroscopic cross-section values were calculated experimentally for each composite material against Pu–Be neutron source. As the conclusion of the study, it could be understood that in spite of decrease of the attenuation coefficient against gamma radiation, the adding materials give rise to increase the shielding ability of material against neutron radiation. [ABSTRACT FROM AUTHOR]

In this study gamma and neutron attenuation properties of boron carbide–aluminium (B4C–Al) composites were investigated. B4C–Al composites were produced by spark plasma sintering method. Aluminum percentages in the B4C–Al composites were 0%, 10%, 15%, and 20% by volume. The composite materials were performed against gamma and neutron sources. Cs-137 and Co-60 gamma radioisotopes were used as gamma sources and Pu–Be neutron howitzer was used for neutron source. Theoretical mass attenuation coefficients were determined by using XCOM computer code and compared with the experimental results. It has been seen that the experimental results were close to the theoretical results. Total macroscopic cross-sections of the samples were determined for Pu–Be neutrons. It is concluded that increasing aluminum ratio in the B4C–Al composites causes higher gamma attenuation behavior for Cs-137 and Co-60 gamma sources and the total macroscopic cross-sections of the B4C–Al composites decrease by increasing Al concentration. [ABSTRACT FROM AUTHOR]

Boron carbide (B4C) ceramics were produced by spark plasma sintering technique with 5, 10, 15, and 20 vol.% aluminum (Al) in order to improve sintering behaviours of B4C ceramics. B4C ceramics were produced, having square cross-section and 50×50×5 mm³ dimensions. The sintering process was carried out at different temperatures by applying 40 MPa of pressure with 100 °C/min under vacuum. The effects of various amounts of Al additive and sintering temperature on density, vickers hardness, fracture toughness and microstructure were examined. The hardness and fracture toughness of the samples were evaluated by the Vickers indentation technique. Microstructures of the samples were characterized by scanning electron microscopy technique. Fast neutron attenuation properties of the ceramics having highest density were also investigated. [ABSTRACT FROM AUTHOR]

Boron carbide is a material which has wide application areas in industry including nuclear technology. Titanium diboride–boron carbide composites which were produced from different boron carbide particle sizes were studied for searching of the behaviour against the gamma ray. Micron size and submicron size boron carbide were used to produce composite materials. The volume of boron carbide and titanium diboride in the composites are 85% and 15%, respectively. For the investigation of the gamma radiation behaviour of these materials, Cs-137 radioisotope was used as gamma source in the experiments which has a single gamma-peak at 0.662 MeV. Gamma transmission technique was used for the measurements. The effects of boron carbide particle size on radiation attenuation of titanium diboride–boron carbide composites were evaluated in relation with gamma transmission and the results of the experiments were interpreted and compared with each other. It could be understood that decrease of particle size of boron carbide in boron carbide–titanium diboride composites causes higher linear and mass attenuation coefficient values. So, submicron size boron carbide used composite materials are more convenient than micron size boron carbide used composite materials as radiation shielding materials for nuclear applications. [ABSTRACT FROM AUTHOR]