Indentation techniques for evaluating the fracture toughness of biomaterials and hard tissues
Indentation techniques for evaluating the fracture toughness of biomaterials and hard tissues
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DOI：
10.1016/j.jmbbm.2008.10.008
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发表时间：
2009-08-01
影响因子：
3.9
通讯作者：
Ritchie, R. O.
中科院分区：
文献类型：
--
作者：
Kruzic, J. J.;Kim, D. K.;Ritchie, R. O.
用于评估断裂韧性的压痕技术由于实验的简单性和便捷性而具有吸引力，并且因为它们有可能表征局部和整体断裂特性。不幸的是，很少有这样的技术被证明能给出准确的断裂韧性值。这是一个值得关注的问题，因为这些技术在生物材料和生物硬组织的研究中越来越多地使用。本文考虑了四种可用的压痕技术：维氏压痕断裂（VIF）试验、立方角压痕断裂（CCIF）试验、维氏裂纹张开位移（VCOD）试验和界面压痕断裂（IIF）试验。根据已发表的有关该主题的文献，讨论了每种技术在评估材料或材料界面的绝对和相对韧性方面的适用性。总的来说，VIF和CCIF技术在定量评价任何脆性材料的韧性方面都很差，而且所涉及的较大误差（类似于+/- 50%）限制了它们作为比较技术的适用性。实际上，压痕韧性值必须至少相差三倍才能得出实际韧性的显著差异。此外，还提出了用CCIF试验评价人皮质骨抗骨折性的新实验结果。这些新结果表明，诱导裂纹是困难的，并且形成的裂纹嵌入在压痕的塑性区，从而使基于线弹性断裂力学的技术来评估与这些裂纹相关的韧性失效。VCOD测试对于某些玻璃来说似乎是一种很好的定量方法，但初步结果表明，将这种技术应用于其他脆性材料可能存在问题。最后，IIF技术只应被视为比较或半定量技术，用于比较材料界面和/或邻近材料。(C) 2008 Elsevier Ltd版权所有。
Indentation techniques for assessing fracture toughness are attractive due to the simplicity and expediency of experiments, and because they potentially allow the characterization of both local and bulk fracture properties. Unfortunately, rarely have such techniques been proven to give accurate fracture toughness values. This is a concern, as such techniques are seeing increasing usage in the study of biomaterials and biological hard tissues. Four available indentation techniques are considered in the present article: the Vickers indentation fracture (VIF) test, the cube corner indentation fracture (CCIF) test, the Vickers crack opening displacement (VCOD) test and the interface indentation fracture (IIF) test. Each technique is discussed in terms of its suitability for assessing the absolute and relative toughness of materials or material interfaces based on the published literature on the topic. In general, the VIF and CCIF techniques are found to be poor for quantitatively evaluating toughness of any brittle material, and the large errors involved (similar to +/- 50%) make their applicability as comparative techniques limited. Indeed, indentation toughness values must differ by at least by a factor of three to conclude a significant difference in actual toughness. Additionally, new experimental results are presented on using the CCIF test to evaluate the fracture resistance of human cortical bone. Those new results indicate that inducing cracking is difficult, and that the cracks that do form are embedded in the plastic zone of the indent, invalidating the use of linear elastic fracture mechanics based techniques for evaluating the toughness associated with those cracks. The VCOD test appears to be a good quantitative method for some glasses, but initial results suggest there may be problems associated with applying this technique to other brittle materials. Finally, the IIF technique should only be considered a comparative or semi-quantitative technique for comparing material interfaces and/or the neighboring materials. (C) 2008 Elsevier Ltd. All rights reserved.