Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Nat Mater. 2011 Oct 24;10(11):817-22. doi: 10.1038/nmat3115.
The attainment of both strength and toughness is a vital requirement for most structural materials; unfortunately these properties are generally mutually exclusive. Although the quest continues for stronger and harder materials, these have little to no use as bulk structural materials without appropriate fracture resistance. It is the lower-strength, and hence higher-toughness, materials that find use for most safety-critical applications where premature or, worse still, catastrophic fracture is unacceptable. For these reasons, the development of strong and tough (damage-tolerant) materials has traditionally been an exercise in compromise between hardness versus ductility. Drawing examples from metallic glasses, natural and biological materials, and structural and biomimetic ceramics, we examine some of the newer strategies in dealing with this conflict. Specifically, we focus on the interplay between the mechanisms that individually contribute to strength and toughness, noting that these phenomena can originate from very different lengthscales in a material's structural architecture. We show how these new and natural materials can defeat the conflict of strength versus toughness and achieve unprecedented levels of damage tolerance within their respective material classes.
获得强度和韧性是大多数结构材料的基本要求；不幸的是，这些性能通常是相互排斥的。虽然人们一直在追求更强硬的材料，但如果没有适当的抗断裂性，这些材料作为块状结构材料几乎没有或根本没有用处。在大多数需要安全关键应用的情况下，较低强度和较高韧性的材料得到了应用，因为过早或更糟糕的灾难性断裂是不可接受的。出于这些原因，传统上，在硬度与延展性之间进行权衡，一直是开发高强度和高韧性（耐损伤）材料的一个过程。我们从金属玻璃、天然和生物材料以及结构和仿生陶瓷中提取了一些例子，探讨了处理这种冲突的一些新策略。具体来说，我们专注于单独对强度和韧性有贡献的机制之间的相互作用，注意到这些现象可能起源于材料结构体系中非常不同的长度尺度。我们展示了这些新型天然材料如何克服强度与韧性之间的冲突，并在各自的材料类别中实现了前所未有的耐损伤能力。
