Chair of Solid Mechanics, University of Wuppertal, Germany.
Chair of Solid Mechanics, University of Wuppertal, Germany.
Acta Biomater. 2020 Apr 15;107:1-24. doi: 10.1016/j.actbio.2020.02.019. Epub 2020 Feb 19.
The most important demand of today's high-performance materials is to unite high strength with extreme fracture toughness. The combination of withstanding large forces (strength) and resistance to fracture (toughness), especially preventing catastrophic material failure by cracking, is of utmost importance when it comes to structural applications of these materials. However, these two properties are commonly found to be mutually exclusive: strong materials are brittle and tough materials are soft. In dental enamel, nature has combined both properties with outstanding success - despite a limited number of available constituents. Made up of brittle mineral crystals arranged in a sophisticated hierarchical microstructure, enamel exhibits high stiffness and excellent toughness. Different species exhibit a variety of structural adaptations on varying scales in their dental enamel which optimise not only fracture toughness, but also hardness and abrasion behaviour. Nature's materials still outperform their synthetic counterparts due to these complex structure-property relationships that are not yet fully understood. By analysing structure variations and the underlying mechanical mechanisms systematically, design principles which are the key for the development of advanced synthetic materials uniting high strength and toughness can be formulated. STATEMENT OF SIGNIFICANCE: Dental enamel is a hard protective tissue that combines high strength with an exceptional resistance to catastrophic fracture, properties that in classical materials are commonly found to be mutually exclusive. The biological material is able to outperform its synthetic counterparts due to a sophisticated hierarchical microstructure. Between different species, microstructural adaptations can vary significantly. In this contribution, the different types of dental enamel present in different species are reviewed and connections between microstructure and (mechanical) properties are drawn. By consolidating available information for various species and reviewing it from a materials science point of view, design principles for the development of advanced biomimetic materials uniting high strength and toughness can be formulated.
当今高性能材料最重要的要求是将高强度与极高的断裂韧性结合起来。承受大力量（强度）和抵抗断裂（韧性）的能力，特别是防止这些材料的灾难性失效，对于它们的结构应用至关重要。然而，这两个特性通常是相互排斥的：强材料易碎，韧材料柔软。在牙釉质中，大自然以出色的成功结合了这两种特性——尽管可用的成分有限。牙釉质由脆性矿物晶体以复杂的层次微观结构排列而成，具有高刚度和优异的韧性。不同物种的牙釉质在不同的尺度上表现出多种结构适应性，不仅优化了断裂韧性，还优化了硬度和耐磨性。由于这些复杂的结构-性能关系尚未完全理解，因此自然材料仍然优于其合成对应物。通过系统地分析结构变化和基础力学机制，可以制定出将高强度和韧性结合起来的先进合成材料的设计原则。
牙釉质是一种坚硬的保护组织，它将高强度与异常的抗灾难性断裂能力结合在一起，而这些特性在经典材料中通常是相互排斥的。由于具有复杂的层次微观结构，生物材料能够超越其合成对应物。在不同物种之间，微观结构适应性可能有很大差异。在本研究中，回顾了不同物种中存在的不同类型的牙釉质，并探讨了微观结构与（力学）性能之间的联系。通过整合各种物种的现有信息，并从材料科学的角度进行审查，可以制定出将高强度和韧性结合起来的先进仿生材料的设计原则。
