| Abstract Scope |
Novel compositionally complex borides, (Hf,Zr,Nb,Ti)B2 and (Hf,Zr,Nb,Ti)B2-LaB6, were fabricated using spark plasma sintering (SPS) process. (Hf,Zr,Nb,Ti)B2-LaB6 exhibits a dual-phase microstructure, in which (Hf,Zr,Nb,Ti)B2 is a primary phase with the hexagonal structure and LaB6 is a secondary phase with a cubic structure. The mechanical properties of both (Hf,Zr,Nb,Ti)B2 and (Hf,Zr,Nb,Ti)B2-LaB6 are comparable, with a combination of high hardness and moderate fracture toughness. Thermal diffusivity and conductivity of (Hf,Zr,Nb,Ti)B2 are much lower than the individual transition metal borides but is significantly increased by the addition of LaB6. Herein, it is implied that the thermal properties of boride ceramics can be controlled through the appropriate design of principal metal element compositions. |
