Atomic-scale investigation of Si/Al interface in multilayer aluminum sheets using HRTEM and first-principle calculation

Abstract

The atomic-scale structure and electronic structure of the interface between Si precipitates and the Al matrix in multi-layered aluminum sheets are investigated by combining high-resolution transmission electron microscopy (HRTEM) with first-principles calculation. The results show that Si needle precipitates and Guinier Preston (GP) zones occur during the natural aging process of the core material in automotive heat exchangers. In addition, Al(Fe,Mn)Si precipitate can serve as effective heterogeneous nucleation sites for the formation of high-density Si precipitates during aging. The charge density differences analysis shows that the formation of covalent bonds between interfacial Si and Al atoms is crucial to the interfacial bonding strength. These results provide important insights for future research efforts focused on the production of multilayer aluminum sheets with high-performance.