应用基于价键理论和能带理论建立的固体与分子经验电子理论(EET)和改进的界面TFD理论,将合金宏观性能的研究追溯到原子成键的电子结构层次,对Al-Mg—Si合金的pre-β"和β"析出相内部原子间的价电子成键及其与基体界面间形成的界面键络特征进行研究,计算析出相的键络强度、界面结合因子、晶体结合能、析出相与基体的界面能。两相的计算结果表明:pre-β"目的界面能较小,析出相需要的形核功较小,因此,该相易于析出;而∥相的界面能较大,则该相形核长大较难;这两个析出相与基体的相界面处的电荷密度连续性好,同时界面的原子键结合较强,使得相界面处内应力较小,界面结合较坚固,能够有效地提高合金的强度和韧性。这些结果与实验情况相符合。
The atomic bonding, interface combination factor, crystal cohesive energy, interface energy between the precipitation and matrix were calculated using the empirical electronic theory in solid (EET), and the improved TFD theory were established basis on bond theory, and it went back to the electronic scale of atomic bonding for researching the macro-property of alloy to investigate the atomic bonding ofpre-β" and β" phase and of interface between the matrix with pre-β" and β" phase. Comparing with the calculation results of the two phase, it shows that the interface energy of pre-β" is smaller, the smaller work energy for nuclear is needed, so the phase is easy to form, while the interface energy of β" phase is larger when the phase is more difficult to form. The calculation result indicates that not only the electronic density is continuous in interface of the two precipitation phase and matrix, but also the atomic bonding in the interface is stronger. The stronger the bonding in interface is, the smaller the inner stress in interface is. The combination solidity of interface has a good effect on enhancing the strength of alloy. The calculation results are good agreement with experiment results.