摘要:
采用改进分析型嵌入原子法(MAEAM)计算了面心立方过渡金属Ni、Pd、Pt、Cu、Ag、Au和Al自扩散过程中的能量。对于最近邻(NN)和次近邻(NNN)二种扩散机制，其能量曲线均为对称曲线且能量的最大值均位于各自扩散路径的中点。计算得到的单空位形成能、迁移能和自扩散激活能比用嵌入原子法(EAM)计算的结果更接近NN扩散的实验数据。计算结果表明NN扩散的激活能最低(迁移能也为最低)，因此面心立方过渡金属中的最可几扩散为单空位最近邻扩散。
Abstract: The energy during the process of self-diffusion in FCC transition metals Ni, Pd, Pt, Cu, Ag, Au and Al has been calculated by using modified analytic embedded-atom method (MAEAM). For each kind of two diffusion mechanisms nearest-neighbor (NN) and next-nearest-neighbor (NNN), the energy curve is symmetric and the maximum value of the energy appears at the middle point of the diffusion path. Determined mono-vacancy formation energy , migration energy and activation energy for self-diffusion agree well with available experimental data of NN diffusion and are better than those obtained by the embedded-atom method (EAM). Compared the energies corresponding to two diffusion mechanisms, the NN diffusion needs the lowest activation energy (and thus the lowest migration energy). So that, the NN mono-vacancy diffusion is favorable in FCC transition metals.