A first-principles study of the formation of θ′′ phase in Al–Cu alloys

The θ′′-Al₃Cu phase plays an important role in the precipitation process of Al–Cu alloys. This phase has a sandwich structure—every two {200}_Cu layers are separated by three {200}_Al layers. To analyse the formation mechanism of this structure, the elastic strain energy of the {200}_Cu and {200}_Al layers, and the chemical bonding energy that reflects the interaction between the electrons in Cu and neighbouring Al atoms are calculated and analysed by first-principles calculations, projected density of states and Bader analysis. Our computation results reveal that this sandwich structure is energetically preferred in the competition of elastic strain and chemical bonding energies. To minimise the elastic strain energy of {200}_Al and {200}_Cu layers, the {200}_Cu layers prefer being apart from each other, whereas the chemical bonding energy favours the opposite arrangement because the intermetallic bond between Al and Cu atoms may form through <i>p</i>-<i>d</i> hybridization.

θ''-Al₃Cu相（θ''-Al₃Cu phase）在Al-Cu合金的析出相变过程中发挥着关键作用。该相具有三明治型晶体结构：每两层{200}Cu晶面层均被三层{200}Al晶面层隔开。为揭示该结构的形成机理，研究团队通过第一性原理计算（first-principles calculations）、投影态密度（projected density of states）分析与巴德分析（Bader analysis），对{200}Cu与{200}Al晶面层的弹性应变能，以及反映Cu原子与邻近Al原子间电子相互作用的化学键合能开展了计算与分析。本研究的计算结果表明，在弹性应变能与化学键合能的竞争中，该三明治结构在能量上更具优势。为最小化{200}Al与{200}Cu晶面层的弹性应变能，{200}Cu晶面层倾向于彼此分离；而化学键合能则支持相反的排布方式，这是由于Al与Cu原子间的金属间键可通过p-d杂化（p-d hybridization）形成。

搜集汇总

背景与挑战

背景概述

该数据集基于第一性原理计算，研究了Al-Cu合金中θ′′-Al3Cu相的形成机制，重点分析了弹性应变能和化学键合能的竞争作用。数据集包含计算数据和相关分析文件，适用于材料科学和合金相变研究领域。