Fabrication and properties of (W+B)/Al hybrid composites for nuclear radiation shielding

A novel non-lead, lightweight nuclear shielding material was developed by introducing W and B particles as functional components into 6061 Al alloy. The ball-milling and spark plasma sintering (SPS) were employed to fabricate the (W+B)/Al hybrid composites. Some dominant process parameters, such as ball milling time, holding time, etc, were optimized. Subsequently, the effect of W volume fraction on the microstructure and mechanical properties as well as radiation shielding performance of the composites were thoroughly investigated. It is demonstrated that the W particles are homogenously distributed throughout the Al matrix with a W volume fraction less than 20 %. Al12W is identified as an interfacial product at the Al-W interface. The composites containing 20 vol% tungsten particles exhibits the highest mechanical strength. When the volume fraction of W particles increases to 30 vol%, severe agglomeration of W particles occurs, and the mechanical properties are considerably deteriorated. Compared with 6061Al, the influence of T6 heat treatment on the strength of the composites is insignificant, especially for the composites with a high W content. The γ-ray shielding properties of the composites are significantly improved with increasing W content. The linear attenuation coefficient is up to 0.32 cm−1 for the composites with 30 vol% W. The thermal neutron absorption rate of the (W+B)/Al composites all achieve 99 % with a thickness of 2.2 cm. The results suggest that the developed (W+B)/Al hybrid composites exhibit extraordinary application potential as a structure-function integrated nuclear shielding materials.