Al-Cu-Mg-Ag合金Ω相价电子结构与沉淀硬化能力的关系

Relationship Between the Valence Electron Structure of Ω and the Ability of Precipitation Hardening in Al-Cu-Mg-Ag Alloys

基于固体与分子经验电子(Empirical electron theory of solids and molecules,EET)理论,计算了Ω相的价电子结构,分析了主键络的空间分布形态,研究了最强共价键与位错运动、共价电子密度与析出相强度、成键能力与析出相稳定性的关系。结果表明:Ω相共价主干键络呈三维“梅花”状分布,“花心”由Cu-Cu原子最强共价键连接;基体α最强共价键的键合力n1α为0.20857,Ω相的n1Ω为0.49056,基体{111}晶面上析出的Ω相使{111}晶面上位错滑移的阻力增加135.20%;从共价电子密度看,Ω相强度比S、θ′相的分别大2.67%和15.83%;从成键能力看,Ω相的稳定性比S和θ′相的分别大91.31%和291.92%;从共价电子结构看,{111}晶面析出的Ω相的沉淀硬化能力比{001}晶面析出的S、θ′相强。

Based on the empirical electron theory of solids and molecules, the VES of Ω phase was calculated in this paper, then the spatial distribution of the primary bond of covalent bonds was analyzed, the relationships between the strongest covalent bond and dislocation motion, the covalent electron density and the precipitate strength, and the bonding ability and the precipitate stability were studied. It is showed that the main bond-net distribution appears plum blossom-like and the flower heart is connected by the strongest covalent bond with Cu-Cu atoms. The bonding force of the strongest covalent bond of the matrix α is 0.208 57 while that of Ω is 0.490 56, so the Ω precipitation from {111} plane of the matrix can make the block of dislocation slip on {111} plane increased by 135.20%. The strength of Ω is 2.67%, 15.83% bigger than that of S and θ′ respectively from the point of view of the covalence electron density. The stability of Ω is 91.31%, 291.92% bigger than that of S and θ′ respectively from the point of view of bonding ability. The precipitation-hardening ability of phase Ω precipitated form {111} plane is stronger than that of phase S and phase θ′ precipitated form {001} plane respectively from the point of view of covalence electron structure.