Molecular dynamics study of the dissolution of crystalline and amorphous nickel nanoparticles in aluminium

Abstract The dissolution of a nickel nanoparticle in aluminium under the conditions of the crystalline and amorphous state of aluminium and nickel, which can be achieved, in particular, with severe plastic deformation of the powders of the initial mixture (mechanoactivation), was studied by means of molecular dynamics. It is shown that the state of the aluminium structure (crystalline or amorphous) has a relatively small effect on the intensity of mutual diffusion of Ni and Al up to the melting temperature of aluminium. This is due to the formation of a crystalline aluminium layer around the crystalline particle, which repeats the Ni lattice. In the case of the amorphous state of the nickel particle and the aluminium matrix, dissolution occurred much faster than in the crystalline state of nickel. That is, mutual diffusion occurs significantly more strongly in the case of the amorphous state of nickel compared to the case of amorphous aluminium at the same constant temperature. The diameter of the nickel nanoparticle in the considered range from 4 to 12 nm did not affect the temperature at which the mutual diffusion of Ni and Al sharply accelerated with varying temperature. This was due to the fact that the melting point of aluminium did not change when simulating particles of different sizes.