Time-dependent deformation and fracture at interfaces of nanostructures

通过对倾斜生长在硅基上的钛纳米柱进行的室温蠕变实验，评价了纳米界面蠕变断裂的主要机制。在恒定的外力作用下，样品以时间相关的方式变形，然后钛纳米柱在界面处断裂。在充分考虑钛纳米柱蠕变的同时，分析了蠕变实验过程中沿钛/硅界面的局部应力分布。在断裂寿命相近的两种试件中，界面边缘附近约5 nm区域的应力非常接近，尽管它们在边缘具有不同的奇异性。这表明蠕变界面断裂是由纳米尺度区域的局部应力场控制的。

The dominant mechanics of creep fracture at interfaces on the nanoscale was evaluated on the basis of creep experiments conducted at room temperature on Ti oblique nanocolumns grown on a Si substrate using glancing angle deposition. The specimens deformed in a time-dependent manner under a constant applied force, and then the Ti nanocolumns fractured at the interface. The local stress distribution along the Ti/Si interface during the creep experiments was analyzed while giving due consideration to the creep of the Ti nanocolumn. The stresses near the interface edge in the region of about 5 nm were very close in the two types of specimens with similar fracture lives although they had different singularities at the edge. This suggested that the creep interfacial fracture was dominated by the local stress field in the nanoscale region.