Inhomogeneous flow and fracture of glassy materials
Inhomogeneous flow and fracture of glassy materials
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DOI：
10.1038/nmat2468
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发表时间：
2009-07-01
期刊：
影响因子：
41.2
通讯作者：
Tanaka, Hajime
中科院分区：
文献类型：
--
作者：
Furukawa, Akira;Tanaka, Hajime
非晶材料的断裂机制是一个长期存在的基本科学问题，在工程的各个领域都具有重要的意义。在一种新型断裂流变模型的基础上，我们证明了与断裂相关的非线性行为是密度波动和变形场之间耦合的结果：剪切引起的密度波动增强通过由此产生的动态和弹性不对称性的增强而自我放大。致密和不致密区域。这种正反馈可能是断裂的起源。我们提出了新的标准的机械不稳定性的发病，从韧性断裂延伸到脆性断裂。通过与我们的模型的数值解和现有的金属和聚合物玻璃形成者的实验结果进行比较，检查它们的有效性。该标准使我们能够预测和设计断裂行为的材料的粘弹性性能的压力依赖性。
The fracture mechanism of amorphous materials, which are of crucial importance in various fields of engineering, remains a long-standing fundamental problem of science despite intensive efforts over the years. On the basis of a novel rheological model of fracture, we demonstrate that nonlinear behaviour associated with fracture is a consequence of the coupling between density fluctuations and deformation fields: shear-induced enhancement of density fluctuations is self-amplified by the resulting enhancement of dynamic and elastic asymmetry between denser and less-dense regions. This positive feedback may be the origin of fracture. We propose novel criteria for the onset of mechanical instability, extending from ductile to brittle fracture. Their validity is checked by comparing them with numerical solutions of our model and existing experimental results of metallic and polymeric glass formers. The criteria enable us to predict and design fracture behaviour of materials from the pressure dependence of their viscoelastic properties.