Interfacial Microstructure and Mechanical Properties of B4C/W Functionally Graded Materials by Spark Plasma Sintering

Integrating boron carbide ceramics (B4C) with tungsten (W) presents great potential for the development of advanced shielding materials. This study focuses on achieving exceptional bonding between B4C and W by fine-tuning the graded interfaces guided by the comprehensive thermodynamic reaction information. The results show that as the W content increases in the graded interlayers, the unstable entropy between B4C and W system drives the reaction progress along the following stages, W2B5 → W2B5 + WB → WB + WC → W2B + W2C. The multi-scale cracks within B4C/W composites and B4C/W graded materials are mainly due to mismatched properties and inherent brittleness of the induced interphases, which can be effectively mitigated by reducing phases such as WB and WC.