(School of Physics Science and Engineering, Guangxi University, Nanning 530004, China)
摘 要: 應用基于價鍵理論和能帶理論建立的固體與分子經(jīng)驗電子理論(EET)和改進的界面TFD理論，將合金宏觀性能的研究追溯到原子成鍵的電子結(jié)構(gòu)層次，對Al-Mg-Si合金的pre-β″和β″析出相內(nèi)部原子間的價電子成鍵及其與基體界面間形成的界面鍵絡特征進行研究，計算析出相的鍵絡強度、界面結(jié)合因子、晶體結(jié)合能、析出相與基體的界面能。兩相的計算結(jié)果表明：pre-β′′相的界面能較小，析出相需要的形核功較小，因此，該相易于析出；而β′′相的界面能較大，則該相形核長大較難；這兩個析出相與基體的相界面處的電荷密度連續(xù)性好，同時界面的原子鍵結(jié)合較強，使得相界面處內(nèi)應力較小，界面結(jié)合較堅固，能夠有效地提高合金的強度和韌性。這些結(jié)果與實驗情況相符合。
關鍵字: Al-Mg-Si合金；析出相；原子成鍵；界面
（School of Physics Science and Engineering, Guangxi University, Nanning 530004, China）
Abstract: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 of pre-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.
Key words: Al-Mg-Si alloy; precipitation; atomic bonding; interface
