Al-Li-Zr合金的界面原子成键与力学性能

Interface atomic bonding and mechanical properties of Al-Li-Zr alloy

应用固体经验电子理论计算Al-Li-Zr合金中若干析出相与基体的界面原子成键强度和异相界面的界面能。结果表明,δ′相与基体之间的界面电子密度在较低的应力下保持连续,使得δ′相与基体界面的结合较好,起到界面增强的效果;δ相与基体间界面电子密度在一级近似下不连续,使得与基体间界面结合强度较弱,引起界面结合弱化。对于核壳结构的复合相δ′/β′,界面电子密度差较小,且界面能最低,使得δ′相容易在β′相上异质形核长大形成复合δ′/β′相。由此从界面原子成键角度揭示析出相对合金起强弱化作用的原因,及其对合金力学性能的影响。

The atomic bonding and interface energy between precipitation and matrix of Al-Li-Zr alloy were calculated by using the ＂Empirical Electronic Theory in Solid＂（EET）.The result shows that the electronic density in interface between δ′ phase and matrix,is continuous under one order approximation at low stress condition,which gets a good combination in interface between δ′ phase and matrix,and strengthens the interface;the electronic density in the interface between δ phase and matrix is not continuous under one order approximation,which make the interface combination weak.For the complex phase δ′/β′ with core and shell structure,not only the interface electronic density is smaller,but also the interface energy is lower,which results to form a complex δ′/β′ phase through the inhomogeneous nucleation of δ′ phase on β′ particles.It can reveal the reason why the precipitation can strengthen and weaken the alloy and thus affect the alloy properties.