B4C-based hard and tough ceramics densified via spark plasma sintering using a novel Mg2Si sintering aid

摘要

? 2022 Elsevier Ltd and Techna Group S.r.l.Full-dense B4C-based ceramics with excellent mechanical properties were fabricated using spark plasma sintering with Mg2Si as a sintering aid at a low temperature of 1675 °C while applying a uniaxial pressure of 50 MPa. The effect of Mg2Si addition on the densification behaviours, mechanical properties and microstructure of as-sintered ceramics were investigated. Not only did the formation of ultra-fine grained SiC using the in-situ reaction effectively inhibit the growth of B4C grains, but it also contributed to the strength and toughness of the resultant ceramics. Additionally, microalloying Mg imparted more metal bonding characteristics to the B4C matrix, thereby improving their ductility. The results indicate that the composite containing 7 wt Mg2Si had excellent mechanical properties, including a light weight of 2.54 g/cm3, Vickers hardness of 34.3 GPa, fracture toughness of 5.09 MPa m1/2 and flexural strength of 574 MPa.