Effects of Ti, Si, Mg and Cu additions on interfacial properties and electronic structure of Al(111)/4H-SiC(0001) interface: A first-principles study

Abstract

In this study, the structural stability and electronic properties of Al(111)/4H-SiC(0001) interface, as well as the effects of Ti, Si, Mg and Cu additions on the interfacial adhesive strength are investigated via the first-principles method. Surface energy calculations show that 4H-SiC(0001) with C-termination is more active than Si-termination. Moreover, polar covalent bonds are formed across Al/4H-SiC interface. The results of separation energies suggest that the introduction of Ti and Si can improve the adhesive strength of C-terminated Al(111)/4H-SiC(0001) interface, whereas Mg and Cu have the opposite effect. According to the analysis of interfacial electronic structure, the covalent bonds across Al/4H-SiC interface are further enhanced with the addition of Ti and Si atoms, contributing to the improved adhesive strength in this case. However, the interactions between interfacial atoms are weakened with Mg and Cu doped in C-terminated interface, which results in the decrease of interfacial adhesion strength. Our calculations provide a guide to experiments on the design of 4H-SiC reinforced Al-matrix composites with tailored properties.