Influences of W contents on microstructures, mechanical properties and the shielding performance for neutrons and γ-rays of Fe–W–C alloy

Abstract

Shielding materials, Fe–W–C alloy (wt.%) with the different tungsten content and higher density was successfully prepared by powder metallurgical processing sequences comprising of mechanical alloying, compaction and liquid phase sintering. The process parameters such as mechanical alloying conditions, compaction pressure, sintering atmosphere, and sintering schedule were optimized to achieve the desired sintered density. The synthesized alloy was characterized for the evolution of microstructure, phases and mechanical properties using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), tensile testing, X-Ray diffraction (XRD), etc. The sintered alloy was found to comprise with the matrix phase a-Fe and the binding phases such as Fe2W2C, Fe6W6C and Fe2W. Extensive, EDS analysis revealed the distribution of Fe, W and C element in the matrix phase, binding phase and blocky binding zone, respectively. W contents altered the density and microstructure of the alloy significantly. The tensile strength and ductility of the as-sintered Fe–W–C alloy was found to be 345 MPa and 17.5%, respectively. SEM characterization of the tensile-fracture surface showed mixed mode of fracture, i.e. ductile and brittle fracture in α-Fe and W particles, respectively. The γ-ray shielding performance of the alloys was carried out by BH1326 γ-ray shielding tester, and the half-attenuation thickness of alloy containing 16% W was the minimum, about 8.5 mm. The results of neutron shielding simulation show that the transmission of the neutron shield of alloy Fe–W–C containing 16% W was the minimum.