Strengthened high-temperature resistance in B4C/SiC/2024Al composite via SiC nanowires pinning grain boundary

Aiming at developing new B 4 C/Al neutron absorbing materials with both high thermal neutron absorption performance and high-temperature strength for neutron shielding applications, B 4 C/SiC/2024Al composites were fabricated by powder metallurgy process. TEM results revealed that SiC nanowires were distributed at Al grain boundaries and bonded tightly with Al matrix . Grain boundary sliding and grain rotation were efficiently restricted and prevented dislocation annihilation at GBs. The thermal stability of composite was improved by adding SiC nanowires and achieved a high-temperature strength of 163.4 ± 1.8 MPa at 573 K, which was increased by 92.2 % compared to the composite without addition of SiC nanowires. By analyzing the strengthening mechanism , dislocation strengthening was the dominant factor in the improvement of high-temperature strength. As for neutron absorption application, B 4 C/SiC/2024Al composite exhibited not only good high-temperature strength but also remarkable neutron absorption performance and matched thermal conductivity and coefficient of thermal expansion .