Development of Al-30% B4C metal matrix composites for neutron absorber material

In recent years, aluminum boron carbide particulate-reinforced composites have been increasingly used as an excellent neutron absorber material in the nuclear industry. Alcan has developed a unique liquid mixing process to manufacture these metal matrix composites. The fabrication of durable and usable components with higher B4C content composites (up to 30%) is challenging in several aspects ranging from mixing, casting, extruding and rolling. In this paper, the results of material development with higher B4C contents, from raw material via semi-finished to finished products, are presented. The casting process, as well as downstream extrusion and rolling processes, are described. The microstructural characteristics of an Al30%B4C composite, as an example, at as-cast and deformed conditions, are reported. The mechanical and material properties of extruded and rolled components at different conditions are examined. Finally, the casting and fabrication of a composite with 25% B4C on the industrial scale are demonstrated.