Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
ACS Appl Mater Interfaces. 2013 Aug 28;5(16):7950-5. doi: 10.1021/am402046e. Epub 2013 Aug 6.
Plasticity plays a crucial role in the mechanical behavior of engineering materials. For instance, energy dissipation during plastic deformation is vital to the sufficient fracture resistance of engineering materials. Thus, the lack of plasticity in brittle hybrid organic-inorganic glasses (hybrid glasses) often results in a low fracture resistance and has been a significant challenge for their integration and applications. Here, we demonstrate that hydrogenated amorphous silicon carbide films, a class of hybrid glasses, can exhibit a plasticity that is even tunable by controlling their molecular structure and thereby leads to an increased and adjustable fracture resistance in the films. We decouple the plasticity contribution from the fracture resistance of the films by estimating the "work-of-fracture" using a mean-field approach, which provides some insight into a potential connection between the onset of plasticity in the films and the well-known rigidity percolation threshold.
塑性在工程材料的力学行为中起着至关重要的作用。例如，塑性变形过程中的能量耗散对于工程材料的充分断裂阻力至关重要。因此，脆性混合有机-无机玻璃（混合玻璃）缺乏塑性往往导致断裂阻力低，这一直是它们集成和应用的重大挑战。在这里，我们证明了氢化非晶硅碳薄膜，一类混合玻璃，可以表现出塑性，甚至可以通过控制其分子结构来调节塑性，从而提高和调节薄膜的断裂阻力。我们通过使用平均场方法估计“断裂功”，从薄膜的断裂阻力中分离出塑性的贡献，这为薄膜中塑性的出现与众所周知的刚性渗流阈值之间的潜在联系提供了一些见解。
