Be-Al合金中Ag和Ni合金化效应的第一性原理研究

First-principles Studies on Alloying Effect of Ag and Ni in Be-Al Alloys

利用第一性原理研究了合金元素Ag和Ni在Be-Al合金中的优先占位方式及其合金化效应。结果表明:Ag和Ni的加入均有助于Be-Al合金稳定性的提高,Ag优先取代Al位,而Ni优先取代Be位;Ag与第一近邻的Be原子形成了反键,使得Be-Al合金体系共价键减少,金属键增加,提高了合金的塑性;Ag掺杂有利于跨界面Be-Al成键,加强了Be-Al界面的结合;Ni加入后与第一近邻原子间的共价键作用减弱,有助于改善合金的脆性,但对Be-Al界面结合强度没有影响。

Site preference behavior of Ag and Ni in Be-Al alloys and alloying effect were studied by using first-principle. Simulated results show that, the addition of alloying element Ag and Ni benefits the improvement of the stability of Be-Al alloys; Ag prefers to occupy the Al site, while Ni prefers to occupy the Be site in Be-Al alloys. The anti-bond between Ag atom and its nearest-neighbor Be atom is formed, which makes the fraction of covalent bond decrease and the fraction of the metallic bonds increase and improves the plasticity of the alloy. The Ag doping enhances the bond between Be and Al that can strengthen the combination of Be/Al interface. The Ni doping decreases the covalent bonds between Ni atom and its nearest-neighbor atom, which facilitates improving Be-Al alloy plasticity, but has no effect on the combination of Be/Al interface.