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本文在Tyson模型的基础上,应用点阵动力学线性响应的理论方法,导出了脆断发生时解理面上原子的响应位移,并进而给出金属脆断表面能的计算公式。这种处理方式既保持了解理断裂面是结晶的表现,避免了局域“熔化”和“沸腾”模拟脆断的简单模型中出现的非晶化问题,也对解理面上原子临界位移做了合理估计,避免了人为规定临界位移的随意性,同时,从理论上得出的脆断时产生的声发射信号与实际探测到的量级相近。用本文中发展的方法,计算了若干体心和面心立方金属的脆断表面能,其结果与实验值为同一数量级。
Based on the Tyson model, a theoretical method of linear response of lattice dynamics is used to derive the response displacements of the atoms on the cleavage plane when brittle fracture occurs, and then the formula for calculating the surface brittle fracture energy is given. This treatment not only maintains the cleavage fracture surface is the crystallization of the performance, to avoid the local “melting” and “boiling” simulated fragile simple model of the emergence of amorphization problem, but also on the cleavage plane atomic displacement A reasonable estimate avoids the arbitrariness of the critical displacement of the man-made regulation. At the same time, the theoretically derived acoustic emission signal from the brittle fracture is similar to the actually detected magnitude. Using the method developed in this paper, the brittle fracture surface energies of a number of body-centered and face-centered cubic metals were calculated and the results were in the same order of magnitude as the experimental values.