Toughening mechanism of B ₄ C/TiB ₂ ceramic materials by in situ reaction via spark plasma sintering

Abstract

Abstract To enhance the fracture toughness of B 4 C ceramics, B 4 C/TiB 2 ceramics with excellent performance were prepared by using TiO 2 as the addition item and using spark plasma sintering to introduce TiB 2 based on in situ reaction, which was compared with ceramics directly introduced with TiB 2 , the impacts of TiO 2 content, temperature and holding time on B 4 C/TiB 2 ceramics were studied, and the toughening mechanism of B 4 C/TiB 2 ceramics in situ reaction was discussed. The results showed that compared with the ceramics directly introduced with TiB 2 , B 4 C/TiB 2 ceramics with reinforcement phase TiB 2 introduced through in‐situ reaction were easier to obtain higher relative density and better properties. Due to the existence of a discharge effect and the application of pulse current, B 4 C/TiB 2 ceramics with excellent comprehensive properties can be prepared at lower temperatures and short time. When 15 vol% TiO 2 was added, the temperature was 1750°C and the holding time was 10 min, the comprehensive properties were better, and their relative density, Vickers hardness, flexural strength, and fracture toughness were 98.5%, 27.72 GPa, 474 MPa, and 5.08 MPa·m 1/2 , respectively. Toughening mechanisms such as crack deflection, crack branching, and crack bridging improved the fracture toughness.