B <sub>4</sub> C–(Ti <sub>0.9</sub> Cr <sub>0.1</sub> )B <sub>2</sub> composites with excellent specific hardness and enhanced toughness
Shuaihang Qiu, Ji Zou, Jingjing Liu, Yanchun Zhou, Wei Ji, Fan Zhang, Weimin Wang, Zhengyi Fu
Abstract
Abstract Dense and light B 4 C–(Ti 0.9 Cr 0.1 )B 2 composites with excellent mechanical properties were designed and reactively densified from boron, TiC, and Cr 3 C 2 powder mixtures by spark plasma sintering in this work. Due to solid solution effects, the as‐obtained B 4 C–(Ti 0.9 Cr 0.1 )B 2 composite exhibited obviously enhanced hardness (43.2 ± 3.0 GPa at 9.8 N) and higher specific hardness (12.82 GPa cm 3 g −1 ) together with improved flexural strength (663 ± 39 MPa) and fracture toughness ( K IC , 5.40 ± 0.25 MPa m 1/2 ), compared to the counterparts such as B 4 C–TiB 2 composite and B 4 C. Toughening contributions in the as‐sintered ceramics were quantitatively analyzed, and higher K IC in B 4 C–(Ti 0.9 Cr 0.1 )B 2 was mainly due to their larger initial fracture toughness and compressive stress toughening. The combination of these properties makes B 4 C–(Ti 0.9 Cr 0.1 )B 2 composites exhibit great potentials in the application as lightweight structural materials. This work provided an inspiration to achieve lightweight materials with high performance through doping minor‐amount atoms into the matrix.