B₄C–(Ti_0.9Cr_0.1)B₂ composites with excellent specific hardness and enhanced toughness

Abstract

Dense and light B4C–(Ti0.9Cr0.1)B2 composites with excellent mechanical properties were designed and reactively densified from boron, TiC, and Cr3C2 powder mixtures by spark plasma sintering in this work. Due to solid solution effects, the as‐obtained B4C–(Ti0.9Cr0.1)B2 composite exhibited obviously enhanced hardness (43.2 ± 3.0 GPa at 9.8 N) and higher specific hardness (12.82 GPa cm3 g−1) together with improved flexural strength (663 ± 39 MPa) and fracture toughness (KIC, 5.40 ± 0.25 MPa m1/2), compared to the counterparts such as B4C–TiB2 composite and B4C. Toughening contributions in the as‐sintered ceramics were quantitatively analyzed, and higher KIC in B4C–(Ti0.9Cr0.1)B2 was mainly due to their larger initial fracture toughness and compressive stress toughening. The combination of these properties makes B4C–(Ti0.9Cr0.1)B2 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.

Tuning mechanical and electrical performances of B 4C–TiB 2 ceramics in a two-step spark plasma sintering process

“…Boron carbide (B 4 C) ceramic has been widely applied in various fields such as military, civil, and nuclear fields due to its light weight, ultra-high hardness, excellent wear resistance, and good neutron absorption capability [1−5]. However, the low fracture toughness (2.0-3.0 MPa•m 1/2 ) and flexural strength (250-450 MPa) as well as the poor sinterability severely hinder the wide application of B 4 C ceramic [6,7]. In addition, the ultra-high hardness and brittle nature make the conventional machining of B 4 C ceramic by diamond lapping or grinding extremely difficult and limited to simple shapes.…”