Size-dependent elastic/inelastic behavior of enamel over millimeter and nanometer length scales
Size-dependent elastic/inelastic behavior of enamel over millimeter and nanometer length scales
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DOI：
10.1016/j.biomaterials.2009.11.045
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发表时间：
2010-03-01
期刊：
影响因子：
14
通讯作者：
Schneider, Gerold A.
中科院分区：
文献类型：
--
作者：
Ang, Siang Fung;Bortel, Emely L.;Schneider, Gerold A.
釉质的微观结构像大多数生物组织一样具有决定其力学行为的分级结构。然而，目前的釉质的力学行为的研究缺乏这些层次的长度尺度的系统调查。在这项研究中，我们进行了宏观单轴压缩测试和不同压头半径的球形压痕，以探测釉质在四个分级长度尺度上的弹性/非弹性转变，即：“大块釉质”（mm），“多棒”（10 μ m），“棒内”（100纳米，具有多个微晶）和最后的“单晶”（10纳米，具有大约一个羟基磷灰石微晶的面积）。在0.4-17 GPa下观察到釉质的弹性/非弹性转变，这取决于长度尺度，并与合成羟基磷灰石微晶的值进行比较。材料的弹性极限是重要的，因为它提供了对材料断裂前的可清洁性的了解。在最小的研究长度尺度（接触半径类似于20 nm），弹性极限其次是塑性变形。在最大的调查长度尺度（接触尺寸类似于2 mm），只有弹性，然后微裂纹诱导的响应进行了观察。从毫米到纳米尺度的弹性/非弹性区域的釉质的地图。可能的潜在机制进行了讨论。(C)2009爱思唯尔有限公司保留所有权利。
The microstructure of enamel like most biological tissues has a hierarchical structure which determines their mechanical behavior. However, current studies of the mechanical behavior of enamel lack a systematic investigation of these hierarchical length scales. In this study, we performed macroscopic uni-axial compression tests and the spherical indentation with different indenter radii to probe enamel's elastic/inelastic transition over four hierarchical length scales, namely: 'bulk enamel' (mm), 'multiplerod' (10's mu m), 'intra-rod' (100's nm with multiple crystallites) and finally 'single-crystallite' (10's nm with an area of approximately one hydroxyapatite crystallite). The enamel's elastic/inelastic transitions were observed at 0.4-17 GPa depending on the length scale and were compared with the values of synthetic hydroxyapatite crystallites. The elastic limit of a material is important as it provides insights into the cleformability of the material before fracture. At the smallest investigated length scale (contact radius similar to 20 nm), elastic limit is followed by plastic deformation. At the largest investigated length scale (contact size similar to 2 mm), only elastic then micro-crack induced response was observed. A map of elastic/inelastic regions of enamel from millimeter to nanometer length scale is presented. Possible underlying mechanisms are also discussed. (C) 2009 Elsevier Ltd. All rights reserved.