The design, microstructure and mechanical properties of B4C/6061Al neutron absorber composites fabricated by SPS

Highlights: • B₄C/6061Al neutron absorber composite was designed and fabricated by spark plasma sintering. • The neutron transmission ratio obviously decreased with the increase of B₄C particle content in the matrix. • B₄C/6061Al neutron absorber composite with 30 vol.% B₄C possesses the best tensile performance. In this study, Monte Carlo N-Particle transport program (MCNP) is first used to calculate the neutron transmission ratio of B₄C/6061Al neutron absorber composites(NACs) with 5 vol.%–40 vol.% B₄C particle content at different thickness in vacuum. Then the composites have been synthesized by means of ball milling followed by spark plasma sintering (SPS). The effects of B₄C particle content on microstructure and mechanical properties of composite were experimentally investigated. Results show that the neutron transmission ratio decreased with the increase of B₄C particle content and the thickness of plate. The B₄C particles were homogeneously distributed in the metal matrix. Density was found to decrease with the increase of B₄C volume fraction. Reaction products of Ti₂B₅, AlB₁₂ and B were observed and identified in the composites. The microscopic electrical discharge in the gaps between the particles can generate plasma which can improve the particle/matrix interfacial bonding strength. With the increase of particle content, the strength of the NACs first increased and then decreased while elongation to fracture was almost decreased. The strengthening mechanism can be attributed to grain refinement, dislocation strengthening, load transfer effect and Orowan strengthening in NACs.