Diffusion Mechanisms near Tilt Grain Boundaries in Ni3Al Intermetallide

Abstract

The paper is devoted to the research of diffusion mechanism in Ni3Al intermetallide over grain boundaries of tilt <111> and <100> by the method of molecular dynamics. It was found that grain boundary diffusion represented the combination of three main mechanisms: migration of atoms along the nuclei of grain boundary dislocations, cyclic mechanism near the nuclei and the formation of the chain of displaced atoms from one nucleus of dislocation to the nucleus of the other one. Diffusion mobility of Ni atoms was essentially bigger than the mobility of Al atoms. Grain boundary slipping and intergrain slipping were also observed during the deformation of the bicrystal.