Al-Cu-Mg合金S相及S/a相界面价电子结构分析

Valence electron structures analysis of S phase and the S/a interface in Al-Cu-Mg alloy

摘要:

基于EET理论,计算了a-Al与S相及S/a相界面的价电子结构,分析了S相价电子结构与析出强化、S/a相界面价电子结构与界面性能的关系。研究表明：S相共价键分布较为均匀,Cu原子将S相原子间键合力最强的4条共价键连接在一起构成主键络。S相析出强化的微观本质在于其最强共价键的键合力比基体a-Al的大135.14%,对位错运动具有较强的阻力作用。S相与基体a-Al形成的(100)_S//(100)_a和(010)_S// _a及(001)_S//(021)_a面的共价电子密度差Dr分别为0.003%、3.564%和5.811%,(100)_S//(100)_a面上的共价电子密度为10.3915 nm^_-2和10.3918 nm^_-2,(010)_S// _a面上的共价电子密度为0.0486 nm^_-2和0.0469 nm^_-2,(001)_S//(021)_a面上的共价电子密度为0.0486 nm^_-2和0.0459 nm^_-2。与(001)_S//(021)_a和(010)_S// _a面相比,(100)_S//(100)_a面的原子键合力与共价电子密度均最大,共价电子密度差最小,界面连续性最好,界面的应力最小。

Abstract:

Based on the empirical electron theory of solids and molecules, the valence electron structures of S phase and the S/a interface were calculated, then the relationships between their VESs and precipitation strength and interface properties were analyzed in Al-Cu-Mg alloys in this paper. It is shown the covalent bond distribution of S phase is uniform and its main bond network is built by four stronger covalent bonds connected by Cu atoms. The nature of precipitation strength of S phase lies in its binding force of the strongest covalent bond is bigger 135.14% than that of the matrix a-Al and causes the stronger inhibition to the dislocation movement. The covalent electron density difference of (100)_S//(100)_a, (010)_S// _aand (001)_S//(021)_ais 0.003%, 3.564%and 5.811% respectively, while the covalent electron density of (100)_S//(100)_ais 10.3915 nm^_-2 and 10.3918 nm^_-2 , and that of (010)_S// _ais 0.0486 nm^_-2 and 0.0469 nm^_-2, and that of (001)_S//(021)_ais 0.0486 nm^_-2 and 0.0459 nm^_-2. Compared with (001)_S//(021)_a和(010)_S// _a, the binding force and covalent electron density of (100)_S//(100)_a is the biggest while its covalent electron density difference is the smallest, so that the interface continuity is the best and the interface stress is the smallest.