Effects of active elements (Si, Cu, Zn, Mg) on the interfacial properties of Fe/Fe2Al5: A first-principles study

Active elements play a crucial role in enhancing the interfacial bonding between matrix and intermetallic in Fe-based materials. In this paper, alloying elements (Si, Cu, Zn, Mg) were innovatively added to study the influence on the strength of Fe/Al alloy with the help of first-principles calculation. The first-principles calculation was used to understand the interface strengthening mechanism at the electronic level. The results show that Al(Fe-Fe)-TOP Fe2Al5(0−20)/Fe(110) is an ideal interface configuration for the following studies. The doping atoms are more inclined to replace the Al atoms at the interface. When replacing Al atom, alloying element Cu, Mg and Zn can significantly improve the bonding strength of Fe2Al5(0−20)/Fe(110) interface, and the effect of Si is weak that can be neglected. Furthermore, the analyses of electronic structure show that the Fe-Al and Fe-Mg bonds are metallic bonds with covalency. The Fe-Si bonds are mainly ionic bonds. There are obvious charge transfer between Cu, Zn and Fe atoms, and the Fe-Cu and Fe-Zn bonds are strong metal bonds. The bonding strength between atoms may be linked to the number of valence electrons they possess. These results provide important insights into enhancing the interfacial adhesion strength of the Fe/Fe2Al5 system in Fe/Al alloys by adding active elements.