Study of static and dynamic behavior of TiB₂-B₄C composite

The microstructure and phase analysis of TiB₂-B₄C composite were investigated by the X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques, and the mechanical properties were studied by improved experimental facilities under quasi-static and dynamic loading conditions. Results show that regular grain of TiB₂ is distributed uniformly in the grown grain of B₄C, and the fracture mechanism of TiB₂-B₄C composite includes intergranular fracture and transcrystalline fracture. In tensile tests, the Flattened Brazilian Disc (FBD) method was introduced to reduce stress concentration between the platens of the test machine and circular boundaries of the specimen. The results of 2D-DIC method show a good agreement with the data obtained by strain gauges, thus proved the validity of the improved experiment facilities. Meanwhile, both the tensile and compressive strength increase with the increasing of strain rates. The reason is mainly attributed to the presence of TiB₂ addition which serves as a strengthening and toughening agent. The comparison of strength and microstructure among the TiB₂-B₄C composite, the pure B₄C and the pure TiB₂ show that the mechanical properties were dominated by the microstructure and fracture mode of the composite.