B4C ceramics toughened by TiB2–graphite-agglomerated inclusions

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2025-02, Vol.922, p.147680, Article 147680
• Main Authors: He, Qianglong, Guo, Wenchao, Shi, Yunwei, Wang, Aiyang, Wang, Weimin, Fu, Zhengyi
• Format: Article
• Language: English
• Subjects: Agglomerated; B4C–TiB2–graphite; Mechanical properties; Microstructure
• ISSN: 0921-5093
• DOI: 10.1016/j.msea.2024.147680

In this study, B4C–TiB2–graphite ceramic composites were prepared via reactive hot-pressing sintering using B4C and TiC as the raw materials. The reaction process, microstructure, and mechanical properties were investigated. The solid-phase reaction is a diffusion-controlled process, wherein the B atoms diffuse into TiC and react to form TiB. Thereafter, TiB2 is generated with the entry of subsequent B atoms. A core–shell structure is formed, wherein TiB2 particles are wrapped by layered graphite. The products TiB2 and graphite inhibit the growth of B4C matrix grains, which are instrumental in fine grain strengthening. In addition, the novel TiB2–graphite-agglomerated structure significantly improves the fracture toughness of the ceramic composites through crack deflection, bridging, and branching toughening mechanisms. Therefore, the comprehensive properties of B4C–TiB2–graphite ceramic composites are better than those of pure B4C ceramics. Specifically, the fracture toughness is approximately 6.77 MPa m1/2, which is considerably higher than that of pure B4C ceramics (2.47 MPa m1/2).