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用扫描隧道显微镜(STM)在纳米尺度研究了Ti_3Al,Ti-24Al-11Nb合金脆断表面特征,确定了STM在纳米尺度测量材料断裂表面分形维数的方法及原理,并用来测量了上面两种合金脆断表面的分形维数D_F。结果表明:在纳米尺度的断口特征与用SEM在微米尺度观察到的断口形貌非常相似,具有典型的解理脆断特征,观察到了纳米数量级解理台阶,断裂表面在纳米尺度上存在分形结构,但不同断裂方向的分形维数D_F不相同,Ti-24Al-11Nb合金的分形维数高于Ti_3Al合金的分形维数。研究表明使用STM并采用连续拓扑结构分形方法研究固体断裂中的原子过程以及用分形维数来描述材料的微观结构是很有可能的。
The characteristics of brittle fracture surface of Ti 3 Al and Ti-24Al-11Nb alloy were investigated by scanning tunneling microscope (STM) at the nanoscale. The method and principle of measuring fractal dimension of STM on the nanoscale were established and used to measure the above two Fractal dimension of brittle fracture surface of alloy D_F. The results show that the fracture characteristics at the nanoscale are very similar to the fracture morphology observed at the micrometer scale with SEM, with the typical features of cleavage and brittle fracture. The order of nanometer scale cleavage steps is observed, and the fracture surface has a fractal structure at the nanoscale , But fractal dimension D_F in different fracture directions is different. The fractal dimension of Ti-24Al-11Nb alloy is higher than that of Ti_3Al alloy. Research shows that it is possible to study the atomic processes in solid fractures and to describe the microstructure of the materials using fractal dimensions using STM and using the method of continuous topological fractal.