Role of boron nitride nanosheet coatings on aluminum substrates during the nanoindentation from the atomic perspective

Molecular dynamics (MD) simulations are performed to study the repeated nanoindentation on aluminum (Al) substrate with different boron nitride nanosheet (BNNS) coating thickness. To reveal the strengthening mech-anism of coating, the hardness, surface morphology, atomic stress, atomic strain and phase transition are analyzed. The results show that the hardness of substrate increases with the coating thickness. It is also revealed that the pressure area of Al substrate increases with coating thickness. Because of the coating force, more atoms move along the loading direction, causing the substrate to slip more and more atoms to be severely strained. However, although severely deformed, some Al atoms still recover elastically after unloading. After multiple loadings, some elastic deformations are transformed into plastic deformations. The lattice structures are destroyed, possibly with amorphous atoms.

Automated summary

Molecular dynamics simulations were used to investigate the repeated nanoindentation on aluminum substrate with varying thicknesses of boron nitride nanosheet coating. The study reveals that the hardness of the substrate increases with coating thickness. The pressure area of the aluminum substrate also increases with coating thickness. The coating force causes more atoms to move along the loading direction, leading to substrate slip and severe atomic strain. However, some aluminum atoms are able to elastically recover after unloading, despite being severely deformed. After multiple loadings, elastic deformations transition into plastic deformations, possibly accompanied by lattice structure destruction and the presence of amorphous atoms.