Boron carbide based composites densified via Ti3SiC2 boronizing with excellent mechanical properties and amorphization tolerance

Abstract

Consolidated boron carbide (B4C) composites are extremely hard but have been shown to undergo stress-induced amorphization when subjected to high velocity impact. This localized amorphization has been related to the sudden loss of their strength and poor ballistic protection. In this work, dense B4C based composites were spark plasma sintered through in-situ reactions involving with Ti3SiC2 and boron. Hierarchical structures composed of TiB2–SiC–Si reinforcement and B4C matrix were finally built and the degree of amorphization was markedly reduced as the increment of boron amounts. As-generated composites with tough and hard reinforcement possess enhanced amorphization resistance without compromising their mechanical properties. Due to the co-doping of Si and B in boron carbide, the amorphization degree yields a reduction of up to 73 %. The dominant amorphous tolerance is associated with the chain retention and atomic-level local lattice distortion in boron carbide. Therefore, Ti3SiC2 boronizing route may present itself a promising strategy to design boron carbide based composites with better ballistic performance.