B4C-(Ti0.9Cr0.1)B2 composites with excellent specific hardness and enhanced toughness

Dense and light B4C-(Ti0.9Cr0.1)B-2 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)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 B4C-TiB2 composite and B4C. Toughening contributions in the as-sintered ceramics were quantitatively analyzed, and higher K-IC in B4C-(Ti0.9Cr0.1)B-2 was mainly due to their larger initial fracture toughness and compressive stress toughening. The combination of these properties makes B4C-(Ti0.9Cr0.1)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.