Al-Cu合金GP区形成过程的价电子结构演变

基于EET理论和Gerold的Al-Cu合金GP区终态原子结构模型,建立GP区价电子结构计算模型,研究GP区价电子结构的演变过程,提出形成过程中GP区点阵常数的计算方法,计算GP区的价电子结构,分析了Cu含量对其价电子结构的影响。结果表明,Al-Cu合金时效过程中GP区是渐进形成的。在形成初期,Spinodal分解机制占主导作用;在形成后期,正常的形核-长大机制占主导作用。随着Cu原子的富集,GP区最强共价A键的共价电子对数nA逐渐增加,B、C、D键的共价电子对数nB、nC、nD逐渐减少。GP区A键变强的原因在于B、C、D键上的共价电子逐渐向A键转移。

Liaoning University of Technology, Jinzhou 121001, China

According to the empirical electron theory of solids and molecules (EET) and Gerold's terminal-state atom model of GP zone of Al-Cu alloy, the calculation model of valence electron structure of GP zone was set up and the evolution process was investigated. Moreover, the calculation method of lattice constant of GP zone during precipitation was proposed, and the valence electron structure of GP zone was calculated. Furthermore, the effect of Cu content on the valence electron structure was also studied. The results show that the formation of GP zone in Al-Cu alloy in early aging is a progressive process. In the initial development of GP zone, the Spinodal decomposition is the dominant mechanism, and in its later period, the dominant mechanism is the normal nucleation-growth mechanism. With aggregating of Cu atom, the covalent electron pairs nA on the strongest covalent bond A increase gradually, but the covalent electron pairs nB, nC and nD on the covalent bonds B, C and D decrease bit by bit. The strengthening of A bond in GP zone is by means of the transfer to A bond of covalent electrons on B, C and D bonds.