Microstructures evolution and mechanical properties of rolled B4C aluminum matrix neutron absorber plate

Abstract

BackgroundBoron carbide (B4C) aluminum matrix composite has a wide application prospect in the field of nuclear power plant spent fuel storage shielding neutron due to the large neutron absorption cross section of B isotope 10B in B4C.PurposeThis study aims to investigate the response mechanism of current effect on the internal microstructure and mechanical properties of neutron absorbing materials.MethodsThe 30wt.% B4C/6061Al neutron absorbing material was prepared by multi-pass rolling after vacuum hot pressing. Electropulsing treatment (EPT) was applied to the heat treatment of prepared materials, and the skin effect and joule effect of current were made use of eliminating the defects and residual stresses at the particle/matrix interface. Finally, energy disperse spectroscopy (EDS), electron backscatter diffractometer (EBSD) and scanning electron microscope (SEM) were employed to observe the microstructure morphology and particle / matrix interface of the samples under different process parameters.ResultsThe results show that the EPT can promote the degree of recrystallization of the matrix alloy, healing heterogeneous particle/matrix interface of micro defects, improve the bonding strength of interface, inhibit grain growth of the matrix alloy, and reduce the interfacial residual stress. With the extension of time of applying pulse current, the tensile strength and elongation of the composite material showed a trend of increase, up to 245.2 MPa and 9.02%, the load transfer effect of B4C particles is enhanced, and the non-thermal effect of current play a leading role.ConclusionsEPT can improve the mechanical properties of B4C aluminum base neutron absorbing material.

Keywords

• b4c/6061al composites
• neutron absorption
• electropulsing
• current effect