Laboratory for Atomistic and Molecular Mechanics (LAMM), Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA, USA; Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA, USA.
Laboratory for Atomistic and Molecular Mechanics (LAMM), Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA, USA; Department of Mechanical Engineering, Politecnico di Milano, via La Masa 1, 20156 Milano, Italy.
J Mech Behav Biomed Mater. 2017 Dec;76:135-144. doi: 10.1016/j.jmbbm.2017.05.007. Epub 2017 May 4.
Creating materials with strength and toughness has been a long-sought goal. Conventional engineering materials often face a trade-off between strength and toughness, prompting researchers seeking to overcome these limitations to explore more sophisticated materials, such as composites. This paradigm shift in material design is spurred by nature, which exhibits a plethora of heterogeneous materials that offer outstanding material properties, and many natural materials are widely regarded as examples of high-performing hybrid materials. A classic example is nacre, also known as mother-of-pearl, which boasts a combination of high stiffness, strength, and fracture toughness. Various microstructural features contribute to the toughness of nacre, including mineral bridges (MBs), nano-asperities, and waviness of the constituent platelets. Recent research in biomimicry suggests that MBs contribute to the high strength and toughness observed in nacre and nacre-inspired materials. However, previous work in this area did not allow for complete control over the length scale of the bridges and had limitations on the volume fraction of mineral content. In this work, we present a systematic investigation elucidating the effects of structural parameters, such as volume fraction of mineral phase and density of MBs, on the mechanical response of nacre-inspired additive manufactured composites. Our results demonstrate that it is possible to tune the composite properties by tuning sizes and content of structural features (e.g. MBs and mineral content) in a heterogeneous material. Looking forward, this systematic approach enables materials-by-design of complex architectures to tackle demanding engineering challenges in the future.
具有高强度和韧性的材料一直是人们长期追求的目标。传统的工程材料通常在强度和韧性之间存在权衡，这促使研究人员寻求克服这些限制，探索更复杂的材料，如复合材料。这种材料设计的范式转变受到自然界的启发，自然界展示了大量具有出色材料性能的异质材料，许多天然材料被广泛认为是高性能混合材料的范例。一个经典的例子是珍珠母，也称为珍珠层，它具有高刚度、高强度和断裂韧性的组合。珍珠层的韧性的各种微观结构特征包括矿物桥（MB）、纳米突起和组成层板的波纹度。仿生学的最新研究表明，MB 有助于珍珠层和珍珠层启发材料中观察到的高强度和韧性。然而，该领域之前的工作无法完全控制桥梁的长度尺度，并且矿物含量的体积分数存在限制。在这项工作中，我们进行了系统的研究，阐明了结构参数（例如矿物相的体积分数和 MB 的密度）对珍珠层启发的增材制造复合材料力学响应的影响。我们的结果表明，可以通过调整异质材料中结构特征（例如 MB 和矿物含量）的尺寸和含量来调整复合材料的性能。展望未来，这种系统的方法使我们能够为复杂结构的材料设计提供未来应对具有挑战性的工程问题的解决方案。
