通过调整润湿性开发具有高抗损伤性能的仿珍珠贝壳层状2024Al/B4C复合材料

为了解决复合材料中B4C陶瓷相难以被金属铝润湿的问题,利用TiH2和B4C的原位反应引入TiB2,进而调节其润湿性和界面结合.通过将熔融合金压力浸渗到冷冻铸造法制备的多孔陶瓷支架中,制备具有层状结构的2024Al/B4C?TiB2复合材料.与2024Al/B4C复合材料相比,加入TiH2后复合材料的抗弯强度和裂纹扩展韧...

Developing nacre-inspired laminate-reticular 2024Al/B4C composites with high damage resistance by adjusting compositional wettability

To address the issue that B₄C ceramics are difficult to be wetted by aluminum metals in the composites, TiB₂ was introduced via an in-situ reaction between TiH₂ and B₄C to regulate their wettability and interfacial bonding. By pressure infiltration of the molten alloy into the freeze-cast porous ceramic skeleton, the 2024Al/B₄C–TiB₂ composites with a laminate-reticular hierarchical structure were produced. Compared with 2024Al/B₄C composite, adding initial TiH₂ improved the flexural strength and valid fracture toughness from (484±27) to (665±30) MPa and (19.3±1.5) to (32.7±1.8) MPa·m^1/2, respectively. This exceptional damage resistance ability was derived from multiple extrinsic toughening mechanisms including uncracked-ligament bridging, crack branching, crack propagation and crack blunting, and more importantly, the fracture model transition from single to multiple crack propagation. This strategy opens a pathway for improving the wettability and interfacial bonding of Al/B₄C composites, and thus produces nacre-inspired materials with optimized damage tolerance.