【摘要】 应用固体经验电子理论(EET),对Al-Cu合金时效过程中θ″、θ′和θ相的键络进行计算。结果表明,时效初期形成的θ″相中,最强共价键为Al-Cu键。合金中θ″相溶解并析出相时,Cu原子状态发生明显变化,使得Cu原子的共价电子数有较大幅度的提高,此时形成的亚稳相的最强共价键仍为Al-Cu键,较θ″相的最强Al-Cu键提高一倍。时效后期,合金析出稳态θ相,最强键由θ′相的Al-Cu键转为Cu-Cu键,而Al-Cu键成为次强键。依靠Cu原子提供较多的共价d电子,使θ相的共价键络较θ′亚稳相的共价键络强度进一步提高。更多还原

【Abstract】 According to "Empirical Electron Theory in solid and molecules"(EET),the valence electron structures of some precipitates of Al-Cu alloy in aging are calculated.The results show that during the early aging,Cu atoms in θ″ phase are at lower hybrid-state than that in copper metal,when the θ″ phase is dissolved and the θ’ phase is formed,the state of Cu atom is enhanced from ninth up to thirteenth hybrid-state which causes the greatly increase of covalence electronic numbers in Cu atoms,so the Cu-Cu covalence bond in θ’ phase is much stronger than that in θ″ phase.When the θ’ phase is dissolved and the θ phase is formed,the state of Cu atoms falls down from the thirteenth hybrid-state to seventh hybrid-state,and the strangest covalence bond is the Cu-Cu covalence bond,much different from the Al-Cu bond in θ″ and θ’ phase.The reason that the covalence bond net in θ phase are much stronger than that in θ″ and θ’ phase is owing to the more d covalence electron offered by Cu atom in θ phase.更多还原