ISSN: 1003-6326
CN: 43-1239/TG
CODEN: TNMCEW

Vol. 32    No. 4    April 2022

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Developing nacre-inspired laminate-reticular 2024Al/B4C composites with high damage resistance by adjusting compositional wettability
Yang WANG, Qiang LIU, Biao ZHANG, Hao-qian ZHANG, Yi-cheng JIN, Zhao-xin ZHONG, Jian YE, Yu-han REN, Feng YE, Wen WANG
(Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China)
Abstract: 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·m1/2, 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.
Key words: bio-inspired composites; freeze casting; titanium hydride; mechanical properties; damage tolerance
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
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