First-principles investigation of interfacial stability, mechanical behavior and failure mechanism of β-SiC(111)/Al(111) interfaces

In this work, the interfacial stability, mechanical behavior and failure mechanism of beta-SiC(1 1 1)/Al(1 1 1) interfaces are systematically investigated by the first-principles simulations based on density functional theory. By stacking the Al(1 1 1) slab with five atom-layers on the beta-SiC(1 1 1) slab with seven atom-layers, C-top, C-center, C-hollow, Si-top, Si-center and Si-hollow interfacial models are established according to their different terminations and stacking sequences. Based on simulated results of interfacial energy, work of adhesion and electron density, the C-top and Si-top models provide the most stable interfacial structures with largest work of adhesion and most stable electronic structure. C-top and Si-top models possess the ultimate tensile strengths of 6.33 and 6.65 GPa, while the tensile strains are separately 10% and 12%. Meanwhile, the tensile interfacial fractures appear in the Al slabs of all six interfacial models. For the C-top and Si-top models, the shear strengths are 5.38 and 5.34 GPa, while the shear strains are 12% and 12% respectively. Moreover, the shear slipping along < 1 <(1)over bar> 0 > directions occur in the Al slabs far from the interface for C-top model and close to the interface for Si-top model. In conclusion, an atomic-scale investigation on interfacial structures and mechanical deformations of beta-SiC/Al interfaces can be brought into light for designing, fabricating and processing new ceramic/metal composites.