Effect of Al2O3np on the Properties and Microstructure of B4Cp/Al Composites

Aluminum-matrix boron carbide (B 4 C p /Al) is a kind of neutron absorbing material widely used in nuclear spent fuel storage. In order to improve the tensile property of B 4 C p /Al composites, a new type of nano-Al 2 O 3 particle (Al 2 O 3np ) reinforced B 4 C p /Al + Al 2 O 3np composites were prepared by powder metallurgy method. The Monte Carlo particle transport program (MCNP) was used to determine the influence of Al 2 O 3np on the thermal neutron absorptivity of composites. The universal material testing machine and scanning electron microscope (SEM) were used to study the mechanical properties, microstructure and fracture morphology of B 4 C p /Al composites. The results indicated that the neutron absorption properties of B 4 C p /Al composites were not affected by the addition of nano-Al 2 O 3 particles in the range of 1 wt%–15 wt%. The addition of Al 2 O 3np can obviously reduce the grain size of B 4 C p /Al matrix metals thus improve the tensile strength of the composites. The addition threshold of Al 2 O 3np is about 2.5 wt%. Both B 4 C p and Al 2 O 3np change the fracture characteristics of the composites from toughness to brittleness, and the latter is more important.