Processing and properties of B ₄ C ceramics reinforced with TiB ₂ ‒CrB ₂ solid solution

Abstract Lightweight boron carbide (B 4 C)‐based composites with optimized mechanical properties were consolidated at 1850°C‒1900°C through a combination of carbide boronizing and spark plasma sintering, with (Ti 0.9 Cr 0.1 )B 2 reinforcement contents systematically varied from 0 to 30 vol.%. Densification behavior analysis revealed that with increasing carbide contents in the reactants, the exothermic reactivity and volumetric shrinkage became more pronounced, facilitating enhanced densification at lower temperatures. Additions of (Ti 0.9 Cr 0.1 )B 2 ‐induced significant grain refinement of B 4 C, the averaged grain size of B 4 C in B 4 C‒20 vol.% (Ti 0.9 Cr 0.1 )B 2 composites (0.71 ± 0.27 µm) is even smaller than those from the raw powders (∼1 µm). B 4 C with 20 vol.% (Ti 0.9 Cr 0.1 )B 2 showed balanced mechanical properties including flexural strength of 620.23 ± 20.01 MPa, fracture toughness of 5.50 ± 0.04 MPa m 1/2 , Vickers hardness ( H v ) of 37.72 ± 1.79 GPa, and a specific hardness of 13.01 GPa cm 3 g −1 . Above enhancement mechanisms were systematically correlated with microstructural characteristics through applications of Griffith's fracture theory.