Tao Yongshu, Li Liang, Miao Guanghong, Dong Jilei
School of Mechanics and Photoelectric Physics, Anhui University of Science and Technology, Huainan 232001, China.
Materials (Basel). 2021 Nov 8;14(21):6718. doi: 10.3390/ma14216718.
Nanocracks can generate at the intersection of the deformation twin and grain boundary (GB). A mathematical model is built to study the nanoinhomogeneity effect on nanocrack nucleation and propagation in the nanocrystalline matrix. The boundary condition at the interface between the nanoinhomogeneity and the matrix is modified by incorporating the interface effect. The influence of the nanoinhomogeneity shear modulus, the nanoinhomogeneity radius, the nanoinhomogeneity position, the interface effect, and the external stress on the nanocrack nucleation and propagation is investigated in detail. The results indicate that the stiff nanoinhomogeneity suppresses nanocrack nucleation and propagation and thereby improves the tensile ductility of nanocomposites without loss of their predominantly high strength. Both the positive interface residual tension and interface elastic constants suppress nanocrack nucleation and propagation, while the negative interface residual tension and interface elastic constants promote nanocrack nucleation and propagation. Furthermore, the effect of interface residual tension is rather significant. The interface elastic constants have a weak effect on nanocrack nucleation and propagation.
纳米裂纹可在形变孪晶与晶界（GB）的交汇处产生。建立了一个数学模型来研究纳米不均匀性对纳米晶基体中纳米裂纹形核与扩展的影响。通过纳入界面效应来修正纳米不均匀性与基体之间界面处的边界条件。详细研究了纳米不均匀性剪切模量、纳米不均匀性半径、纳米不均匀性位置、界面效应和外应力对纳米裂纹形核与扩展的影响。结果表明，刚性纳米不均匀性抑制纳米裂纹的形核与扩展，从而提高纳米复合材料的拉伸延展性，同时不损失其主要的高强度。正的界面残余张力和界面弹性常数均抑制纳米裂纹的形核与扩展，而负的界面残余张力和界面弹性常数则促进纳米裂纹的形核与扩展。此外，界面残余张力的影响相当显著。界面弹性常数对纳米裂纹形核与扩展的影响较弱。
