From brittle to ductile fracture of bone
From brittle to ductile fracture of bone
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DOI：
10.1038/nmat1545
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发表时间：
2006-01-01
期刊：
影响因子：
41.2
通讯作者：
Fratzl, P
中科院分区：
文献类型：
--
作者：
Peterlik, H;Roschger, P;Fratzl, P
韧性对骨骼的结构功能至关重要。通常，材料的韧性不仅取决于其成分，还取决于其微观结构在不扩展裂纹的情况下耗散变形能的能力（1）。聚合物通常能够通过粘塑性流动或非连接微裂纹的形成来耗散能量（2）。在陶瓷中，众所周知的增韧机制是基于裂纹韧带桥接和裂纹偏转（3）。有趣的是，所有这些现象都在骨（4-12）中被鉴定，骨是纤维聚合物（胶原）和陶瓷纳米颗粒（碳酸化羟基磷灰石）的复合物（13-16）。在这里，我们使用控制裂纹扩展实验来解释纤维取向对操纵各种增韧机制的影响。我们发现，断裂能的变化由两个数量级取决于胶原蛋白的取向，和胶原蛋白和裂纹扩展方向之间的角度是决定性的在不同的增韧机制之间的切换。
Toughness is crucial to the structural function of bone. Usually, the toughness of a material is not just determined by its composition, but by the ability of its microstructure to dissipate deformation energy without propagation of the crack(1). Polymers are often able to dissipate energy by viscoplastic flow or the formation of non-connected microcracks(2). In ceramics, well-known toughening mechanisms are based on crack ligament bridging and crack deflection(3). Interestingly, all these phenomena were identified in bone(4-12), which is a composite of a fibrous polymer (collagen) and ceramic nanoparticles (carbonated hydroxyapatite)(13-16). Here, we use controlled crack-extension experiments to explain the influence of fibre orientation on steering the various toughening mechanisms. We find that the fracture energy changes by two orders of magnitude depending on the collagen orientation, and the angle between collagen and crack propagation direction is decisive in switching between different toughening mechanisms.