The design, microstructure and tensile properties of B4C particulate reinforced 6061Al neutron absorber composites

Based on the Monte Carlo Particle transport program MCNP, a novel boron carbide particulate reinforced 6061Al composite for neutron shielding (B4C/6061Al NACs) with high strength and low density was designed. The NACs with four volume fractions (10%, 20%, 30% and 40%) were successfully fabricated by vacuum hot pressing followed by hot rolling (VPHR) in atmospheric environments. The calculation results indicated that the neutron transmission ratio decreased with the increasing of B4C content and the thickness of plates. B4C particle is uniformly distributed in the matrix, exhibiting the good bonding in interface. The phases of neutron absorbers were mainly B4C and Al, and a spot of AlB2 and Al3BC. The grain of the matrix was refined and the dislocation was formed around the particles. With increasing the B4C content, the particles gathered, breakage appeared, and the tensile strength of composite first increased and then decreased. The failure mode of B4C/6061Al NACs included: the interfacial debonding and the cleavage fracture of particles.