Cost-effective fabrication of bio-inspired nacre-like composite materials with high strength and toughness
Cost-effective fabrication of bio-inspired nacre-like composite materials with high strength and toughness
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DOI：
10.1016/j.compositesb.2020.108414
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发表时间：
2020-09
影响因子：
13.1
通讯作者：
Hong-hao Wan;N. Leung;Sana Algharaibeh;T. Sui;Qiang Liu;H. Peng;B. Su
中科院分区：
文献类型：
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作者：
Hong-hao Wan;N. Leung;Sana Algharaibeh;T. Sui;Qiang Liu;H. Peng;B. Su
研究了一种基于双向冷冻铸造的一步致密化工艺，制备了具有独特微层状结构的类珍珠质氧化铝/聚甲基丙烯酸甲酯（PMMA）复合材料。这种方法具有加工时间更短的优点，因为它只需要烧结一次，而不是通过冷冻铸造制造传统的砖和砂浆（BM）复合材料的两次。通过调整工艺参数，获得了不同陶瓷含量和陶瓷层厚度的复合材料。结果表明，陶瓷含量和壁厚对μL复合材料的力学性能有显著影响。具有细陶瓷壁（8 μm）和相对高的陶瓷分数（72体积%）的μL复合材料表现出高弯曲强度（178 MPa）和断裂韧性（12.5 MPa m1/2）的优异组合。并与传统的BM复合材料进行了比较。尽管两种复合材料的断裂行为表现出相似的外在增韧机制，但与包含短陶瓷壁（即砖）的BM复合材料相比，具有较长陶瓷壁的μL复合材料在强度和断裂韧性方面表现出上级机械性能，这是由于复合材料内承载陶瓷相的应力传递的有效性。
A cost-effective one-step densification process based on bi-directional freeze casting was investigated to produce nacre-like alumina/poly (methyl methacrylate) (PMMA) composites with a unique micro-layered (μL) architecture. This method has the advantage of shorter processing time, as it requires only sintering once instead of twice as in the fabrication of conventional brick-and-mortar (BM) composites via freeze casting. By tuning the processing parameters, composites with different ceramic content and layer thickness were obtained. The resultant mechanical properties of μL composites showed that ceramic content and wall thickness affected mechanical properties significantly. The μL composite with fine ceramic walls (8 μm) and relatively high ceramic fraction (72 vol%) exhibited an exceptional combination of high flexural strength (178 MPa) and fracture toughness (12.5 MPa m1/2). The μL composites were also compared with the conventional BM composites. Although the fracture behaviour of both composites exhibited similar extrinsic toughening mechanisms, the μL composites with longer ceramic walls displayed superior mechanical properties in terms of strength and fracture toughness in comparison with the BM composites comprising short ceramic walls (i.e. bricks), due to the effectiveness of stress transfer of load-bearing ceramic phase within the composites.