Structural-functional integrated TiB2/Al–Mg-Gd composite with efficient neutron shielding phases and superior mechanical properties

Abstract

The structural-functional integrated TiB2/Al–Mg-Gd composite was fabricated by the powder metallurgy-based methods, including atomized composite powder fabrication, spark plasma sintering and hot extrusion techniques. In this manner, the atomization process effectively refined Gd-contained phases and dispersed TiB2 particles in composite powders. Such refinement was inherited to the as-extruded composite. In detail, the finer Gd-contained phase was confirmed to be τ(MgNi2-type) Laves phase. Functionally, the composite had high thermal neutron shielding efficiency (99%), which was higher than the published results for neutron shielding materials. This phenomenon was analyzed by the Shmakov-Yamamoto model. The theoretical simulation showed that the refinement of τ phases played a key role in improving the neutron shielding property, which agreed well with experiment results. Structurally, the yield strength, tensile strength and elongation of the TiB2/Al–Mg-Gd composite were 353 ± 5 MPa, 464 ± 6 MPa and 15.6 ± 0.4%, respectively. Such mechanical properties were considerably higher over available neutron shielding materials. Regarding the improved yield strength, both solution strengthening effect and grain refinement strengthening effect were quantitatively analyzed to be the major strengthen contributors. Finally, this novel composite can be a promising candidate for neutron shielding materials in future.