Influence of Ni-Al interphase boundary orientation on the interdiffusion rate at temperatures above aluminum melting point: a molecular dynamics study

The influence of the orientation of Ni-Al interphase boundary relative to the nickel crystal lattice on the intensity of interdiffusion at temperatures above the melting temperature of aluminum was studied by the method of molecular dynamics. It was observed that the boundary between the crystalline and liquid phases was, in fact, shifted by two or three atomic planes into the aluminum phase – a thin layer of aluminum near the boundary retained a crystalline structure that repeated the nickel lattice. As the temperature increased, the thickness of the Al crystalline layer near the boundary decreased. The concentration curves were obtained after modeling interdiffusion at various temperatures for (111) and (001) orientations of the interphase boundary with respect to the Ni lattice. The parts of the curves responsible for the diffusion of Al atoms into crystalline Ni turned out to be similar for both orientations. However, the more sloping parts related to the diffusion of Ni atoms into liquid Al differed: diffusion of Ni atoms into Al proceeded more intensively at the (111) boundary orientation and slower at orientation (001).