By using vacuum sintering method, the shielding materials made of iron-tungsten-carbon-boron (Fe-W-C-B) alloys with different boron (B) contents were prepared. The influences of different B contents on mechanical properties, shielding performance and microstructures of the alloys were investigated. The research results showed that with increasing B content, the fracture of alloys changed from plastic to brittle fractures and the higher the B content was, the more serious the brittle fracture. Moreover, the content of brittle amorphous phase FeWB increased and therefore the hardness and density of alloys increased at first and then reduced. When the B content was 2.5%, the alloy phase was mainly composed of Fe2B, Fe3(C, B) and alpha-Fe phases, with compact microstructure, shown as continuous network microstructure and tiny, long, round rod-like microstructure. In this case, the density, tensile strength and hardness of alloys were 10.05 g/cm(3), 410 MPa and 468 HV, respectively. The gamma-ray shielding performance of the alloy reduced at first, then increased and finally declined with the increase of B contents. When the B content was 1.5%, the half-value thickness reached to the minimum (about 6.36 mm). The transmittance of neutron shields reduced at first and then increased in a low-energy zone (0-4 MeV). When the B content was 2.5%, the alloys showed the lowest transmittance about 0.10842. (C) 2019 Elsevier B.V. All rights reserved.