基体合金元素对SiC/Al界面结合影响的第一性原理及实验研究

采用基于密度泛函理论的第一性原理及实验相结合的方法, 探讨了Al基体中分别掺杂Mg、Si、Cu合金元素对SiC/Al界面结合的影响, 重点考察了合金元素在界面偏聚时的电子结构和成键情况。研究表明: 在未掺杂Al/SiC体系界面结构优化时, 以Si原子为终止面的Brigde结构是最稳定的结合方式; 当合金元素分别替换界面处的Al原子后, 界面处原子的分波态密度、Muliken电荷及成键原子集居数等电子结构参数均有不同程度的变化, 这不仅增加了界面处 Si与Al原子结合, 同时也增强了界面处和亚界面处的Al基体和SiC增强相原子之间的相互作用, 使体系更加稳定, 界面黏着功均有不同提升; 其中掺Mg提升效果最明显, 其次为掺Cu和掺Si; 利用第一性原理计算的掺杂Al/SiC体系黏着功和实验值较为接近且变化规律相同。

Alloy Elements on SiC/Al Interface: a First-principle and Experimental Study

First-principle approach based on density functional theory and experimental method were used to study the interface bonding of SiC/Al substituted by alloy elements Mg, Si and Cu. The electronic structure and bonding of alloy elements at interface segregation were investigated. The results show that bridge-site model with bridge Si is the most stable combination way of SiC/Al interface after optimization of the interface structure of pure Al/SiC system. When Al atoms at the interface replaced by alloy elements separately, the electronic structural parameters such as partial density of states, Mulliken charge and bonding population, all vary in different degree, which not only increase the binding of Si and Al atoms at the interface, but also increase the interaction among alloy atoms, Al matrix and SiC reinforcement at the interface and sub-interface. It is conducive to enable the system more stable and the adhesion work of interface more differently. Among them, the increased adhesion work is the most obvious when Mg is doped, followed by Cu and Si. Furthermore, the adhesion work of Al/SiC systems doped alloy elements calculated by first-principle is close to the experimental values, and the law of change is the same.