Fracture resistance of Cu/Nb metallic nanolayered composite
Fracture resistance of Cu/Nb metallic nanolayered composite
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DOI：
10.1557/jmr.2019.115
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发表时间：
2019-05
影响因子：
2.7
通讯作者：
Sixie Huang;Caizhi Zhou
中科院分区：
文献类型：
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作者：
Sixie Huang;Caizhi Zhou
在这项工作中，进行了分子动力学模拟，以探索 Cu/Nb 金属纳米层复合材料 (MNC) 的裂纹扩展和断裂行为。本研究结果与之前的实验结果一致，说明Cu层和Nb层中的裂纹在等应变加载条件下可能表现出不同的扩展路径和距离。分析表明，该界面可以通过提供位错源在裂纹前端产生塑性应变来提高Cu/Nb MNCs中Nb层的断裂抗力。增加层厚度可以增强Cu层和Nb层的断裂抗力，因为激活位错运动的临界应力随着层厚度的增加而减小。此外，多晶Cu/Nb样品中的晶界（GB）会促进裂纹沿晶界扩展，即晶间断裂，从而降低Nb层的断裂抗力，而在MNC中引入晶界不会改变界面和层厚对MNC断裂抗力的影响。
In this work, molecular dynamics simulations to explore the crack propagation and fracture behavior of Cu/Nb metallic nanolayered composites (MNCs) were performed. The results of this study are consistent with the previous experimental results, which illustrated that cracks in Cu and Nb layers may exhibit different propagation paths and distances under the isostrain loading condition. The analysis reveals that the interface can increase the fracture resistance of the Nb layer in Cu/Nb MNCs by providing the dislocation sources to generate the plastic strain at the front of the crack. Increasing the layer thickness can enhance the fracture resistance of both Cu and Nb layers, as the critical stress for activating the dislocation motion decreases with the increment of the layer thickness. In addition, grain boundaries (GBs) in polycrystalline Cu/Nb samples would decrease the fracture resistance of Nb layer by promoting the crack propagate along the GBs, i.e., intergranular fracture, while the effect of interface and layer thickness on the fracture resistance of MNCs will not be altered by introducing the GBs in MNCs.