Materials Science and Engineering Department, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
SIMaP, Grenoble INP, CNRS, Univ. Grenoble Alpes, F-38000, Grenoble, France.
Nat Commun. 2018 Dec 7;9(1):5249. doi: 10.1038/s41467-018-07614-y.
Interfacial toughening in composite materials is reasonably well understood for static loading, but little is known for cyclic loading. Here, we demonstrate that introducing an interfacial molecular nanolayer at the metal-ceramic interface of a layered polymer-metal-ceramic stack triples the fracture energy for ~75-300 Hz loading, yielding 40% higher values than the static-loading fracture energy. We show that this unexpected frequency-dependent toughening is underpinned by nanolayer-induced interface strengthening, which facilitates load transfer to, and plasticity in, the polymer layer. Above a threshold interfacial bond strength, the toughening magnitude and frequency range are primarily controlled by the frequency- and temperature-dependent rheological properties of the polymer. These results indicate the tunability of the toughening behavior through suitable choice of interfacial molecular layers and polymers. Our findings open up possibilities for realizing novel composites with inorganic-organic interfaces, e.g., arresting crack growth or stimulating controlled fracture triggered by loads with specific frequency characteristics.
复合材料的界面增韧在静态加载下已得到合理的理解，但在循环加载下知之甚少。在这里，我们证明了在层状聚合物-金属-陶瓷叠层的金属-陶瓷界面引入界面分子纳米层，可以将断裂能提高三倍，在 75-300 Hz 加载下，断裂能比静态加载下提高 40%。我们表明，这种出乎意料的频率相关增韧是由纳米层诱导的界面强化支撑的，这有利于向聚合物层传递负载并促进其塑性。在界面结合强度的阈值以上，增韧幅度和频率范围主要由聚合物的频率和温度相关流变特性控制。这些结果表明，可以通过选择合适的界面分子层和聚合物来调整增韧行为。我们的发现为实现具有无机-有机界面的新型复合材料开辟了可能性，例如，阻止裂纹扩展或刺激由具有特定频率特性的负载引发的受控断裂。
