First-principles investigation of interface atomic arrangement and segregation behavior of solute elements in Al/TiC interface in TiC/2219 composites

The interface atomic arrangement and solute element segregation behavior at the Al/TiC interface in TiC/2219 composite material were systematically studied using first-principles calculations. The computational results demonstrate that the (100) Al/TiC (C-site) interface is identified as the theoretically optimal binding interface due to its minimal mismatch, lowest interface energy, and maximum adhesion energy. Among various major and minor solute elements in the 2219 alloy, Fe and Zn exhibit a tendency to spontaneously segregate towards the interface, while Cu, Mn, Si, Mg, Zr, V, and Ti require external energy input to facilitate segregation towards the interface. First-principles tensile experiments reveal that Mg, Zn, and Cu decrease the interface strength, whereas Mn, Fe, Si, Zr, V, and Ti enhance the interface strength. Notably, Mn segregation to the interface maximally enhances the interface bonding strength. Further electronic structure analysis indicates that the weakening of interface bonding by Mg, Zn, and Cu is attributed to the reduction in interface charge density and weakening of interface chemical bonds upon their segregation. Conversely, segregation of Mn, Fe, Si, Zr, V, and Ti results in increased interface charge density, and projection of density of states reveals that Mn atoms form covalent bonds between interface atoms, significantly enhancing the interface atomic bonds and strength. This theoretical analysis discusses the influence of various major and minor solute elements in the 2219 alloy on the Al/TiC interface, providing theoretical insights for interface modification and further enhancement of properties in 2219/TiC composite materials.