Hierarchical flexural strength of enamel: transition from brittle to damage-tolerant behaviour
Hierarchical flexural strength of enamel: transition from brittle to damage-tolerant behaviour
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DOI：
10.1098/rsif.2011.0498
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发表时间：
2012-06-07
影响因子：
3.9
通讯作者：
Schneider, Gerold A.
中科院分区：
文献类型：
--
作者：
Bechtle, Sabine;Oezcoban, Hueseyin;Schneider, Gerold A.
硬质生物材料通常以某种自相似的方式从纳米尺度到宏观尺度进行分层结构，由被软蛋白质壳包围的矿物单元组成。正在进行相当大的努力来模仿这种材料，因为它们的结构优化的机械功能是硬的和刚性的以及损伤容限。然而，目前还不清楚不同的层次如何相互作用，以实现这一业绩。在这项研究中，我们认为牙釉质作为一个具有代表性的，生物层次结构，并确定其弯曲强度和弹性模量在三个层次使用聚焦离子束（FIB）制备的微米尺寸的杠杆。结果进行了比较和分析，使用的理论模型提出的Jager和Fratzl和高和同事开发。这两个属性随着层次尺寸的增加而降低，沿着，同时机械行为从线性弹性转变为弹性-非弹性。我们发现高的模型与结果非常吻合。
Hard, biological materials are generally hierarchically structured from the nano-to the macro-scale in a somewhat self-similar manner consisting of mineral units surrounded by a soft protein shell. Considerable efforts are underway to mimic such materials because of their structurally optimized mechanical functionality of being hard and stiff as well as damage-tolerant. However, it is unclear how different hierarchical levels interact to achieve this performance. In this study, we consider dental enamel as a representative, biological hierarchical structure and determine its flexural strength and elastic modulus at three levels of hierarchy using focused ion beam (FIB) prepared cantilevers of micrometre size. The results are compared and analysed using a theoretical model proposed by Jager and Fratzl and developed by Gao and co-workers. Both properties decrease with increasing hierarchical dimension along with a switch in mechanical behaviour from linear-elastic to elastic-inelastic. We found Gao's model matched the results very well.