Experimental characterization at nanoscale of single crystal silicon fracture toughness
Experimental characterization at nanoscale of single crystal silicon fracture toughness
复制标题
DOI：
10.3221/igf-esis.47.31
复制
发表时间：
2018-12
期刊：
影响因子：
--
通讯作者：
P. Gallo;T. Sumigawa;T. Kitamura
中科院分区：
文献类型：
--
作者：
P. Gallo;T. Sumigawa;T. Kitamura
该工作回顾了最近一些旨在评估硅断裂韧性的初步微观机械测试。结合临界距离理论（TCD）对预裂纹纳米样品和替代缺口纳米样品进行了比较。结果表明，无论采用何种程序（即预裂样品或 TCD），硅的断裂韧性约为 1 MPa·m0.5。该值与宏观对应值一致，即0.75-1.08 MPa·m0.5，因此KIC与尺寸和晶体取向无关。然而，通过使用 TCD，目前非常具有挑战性的最终裂纹尖端的精确控制通过使用缺口样本得以克服。此外，结果还提供了有关纳米尺度裂纹扩展的信息。看来，尽管试样轴偏离（011），但裂纹沿解理面（011）扩展，并且通过破坏裂纹尖端的共价键，该过程发展得非常快。本文最后简要讨论了连续介质理论的崩溃和纳米级断裂力学的挑战。
The work reviews some preliminary recent micromechanical tests aimed at the evaluation of the fracture toughness of silicon. Pre-cracked nano specimens and alternatively notched nano specimens combined with the theory of critical distances (TCD) are compared. The results show that the fracture toughness of silicon is approximately 1 MPa·m0.5, regardless of the procedure involved (i.e., pre-cracked samples or TCD). This value agrees with macro counterpart, i.e., 0.75-1.08 MPa·m0.5, and therefore the KIC is independent of the size and crystal orientation. However, by employing the TCD, the accurate control of the final crack tip which is currently very challenging, is overcome by using notched specimens. Additionally, the results give information about the crack propagation at the nanoscale. It seems that although the specimen axis deviates from the (011), the crack propagates along the cleavage plane (011) and the process develops very fast by breaking covalent bond at the crack tip. A brief discussion on beyond the breakdown of continuum theory and challenges toward nanometer scale fracture mechanics concludes the paper.