Al − BN interaction in a high-strength lightweight Al/BN metal-matrix composite: Theoretical modelling and experimental verification

In recent years, there has been a great interest in the application of h-BN as a reinforcing phase in Al-based metal-matrix composites. The formation of intermediate phases, such as AlN and AlB₂, was frequently reported that had a positive effect on material strength. The present paper gives a detailed description of diffusion-controlled phase transformations in Al/BN composites produced by spark plasma sintering. The resulting structures have been thoroughly studied by a combination of X-ray diffraction, scanning electron microscopy, high-angle annular dark-field scanning transmission electron microscopy, and energy-dispersive spectroscopy. The phase transformations were investigated using density functional theory to support experimental observations.