Abstract: The difference in electrochemical behavior between reinforcement and metal matrix usually damages the corrosion resistance of composites. Herein, the coherent BNNSs-AlN-Al transition interface is creatively constructed in the Aluminium-Boron nitride nanosheets (Al-BNNSs) system based on reactive sintering. It is demonstrated that BNNSs/Al composites exhibit good corrosion resistance via interfacial modification. The BNNSs-AlN-Al transition interface not only optimizes the interfacial structure of BNNSs/Al composites but also significantly enhances the interface bonding strength. Many low-angle grain boundaries (LAGBs) are induced during extrusion due to the pinning effect of strong bonding transition interface. Besides, density functional theory (DFT) calculation and geometric phase analysis (GPA) were executed to clarify the influence of interface design on the corrosion behavior of BNNSs/Al composites. It is found that the transition interface and LAGBs have strong valence electron constraint ability, thus weakening the galvanic effect in composites. Also, the construction of the transition interface reduces the geometrically necessary dislocations and lattice distortion in the grains of Al matrix, avoiding the decrease of corrosion potential of Al matrix. Ultimately, the coupling effect between LAGB and transition interface not only significantly enhances the ion erosion resistance of composites, but also shifts the corrosion mechanism from intergranular corrosion (IGC) to pitting corrosion (PC) in Al matrix. The current work provides a feasible route for the design of aluminum matrix composites (AMCs) with high corrosion resistance.

Key words: BNNSs/Al composites, Coherent transition interface, Corrosion potential, Corrosion resistance