Synchrotron X-ray diffraction study of load partitioning during elastic deformation of bovine dentin
Synchrotron X-ray diffraction study of load partitioning during elastic deformation of bovine dentin
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DOI：
10.1016/j.actbio.2009.11.017
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发表时间：
2010-06-01
影响因子：
9.7
通讯作者：
Dunand, D. C.
中科院分区：
文献类型：
--
作者：
Deymier-Black, A. C.;Almer, J. D.;Dunand, D. C.
牙本质是一种生物复合材料，由刚性羟基磷灰石（HAP）纳米片在顺应性胶原基质中组成，其弹性特性由这两相的体积分数和它们之间的载荷传递决定。我们用高能X射线衍射法测量了室温下牛牙本质HAP相在一系列静态压应力作用下的弹性应变。发现表观HAP弹性模量（施加的应力与弹性HAP应变的比率）为18 +/-2GPa。该值显著低于由下限负荷转移Voigt模型预测的44 GPa的值，该模型使用通过热重分析确定的HAP和胶原体积分数。这种差异是由以下原因解释的：（i）由于界面体积的高分数，纳米尺寸的HAP血小板的固有杨氏模量降低，以及（ii）由于牙本质小管周围的应力集中，局部应力增加。(C)2010由Elsevier Ltd.代表Acta Materialia Inc.出版。
The elastic properties of dentin, a biological composite consisting of stiff hydroxyapatite (HAP) nano-platelets within a compliant collagen matrix, are determined by the volume fraction of these two phases and the load transfer between them. We have measured the elastic strains in situ within the HAP phase of bovine dentine by high energy X-ray diffraction for a series of static compressive stresses at ambient temperature. The apparent HAP elastic modulus (ratio of applied stress to elastic HAP strain) was found to be 18 +/- 2 GPa. This value is significantly lower than the value of 44 GPa predicted by the lower bound load transfer Voigt model, using HAP and collagen volume fractions determined by thermo-gravimetric analysis. This discrepancy is explained by (i) a reduction in the intrinsic Young's modulus of the nano-size HAP platelets due to the high fraction of interfacial volume and (ii) an increase in local stresses due to stress concentration around the dentin tubules. (C) 2010 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.