| Abstract: | Aluminum-matrix boron carbide (B_4C_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_4C_p/Al composites,a new type of nano-Al_2O_3 particle (Al_2O_(3np)) reinforced B_4C_p/Al + Al_2O_(3np) composites were prepared by powder metallurgy method.The Monte Carlo particle transport program (MCNP) was used to determine the influence of Al_2O_(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_4C_p/Al composites.The results indicated that the neutron absorption properties of B_4C_p/Al composites were not affected by the addition of nano-Al_2O_3 particles in the range of 1 wt%-15 wt%.The addition of Al_2O_(3np) can obviously reduce the grain size of B_4C_p/Al matrix metals thus improve the tensile strength of the composites.The addition threshold of Al_2O_(3np) is about 2.5 wt%.Both B_4C_p and Al_2O_(3np) change the fracture characteristics of the composites from toughness to brittleness,and the latter is more important. |
