Migration of tilt boundaries in nickel and Ni3Al intermetallide: a molecular dynamics study

Abstract

The study of migration of <100> and <111> tilt boundaries in Ni and the Ni3Al intermetallide is performed by the molecular dynamics method. It is shown that in Ni and Ni3Al, the low-angle <100> boundaries migrate much slower than the <111> boundaries (approximately twice at a temperature of 1700 K) due to the difference in the mechanisms of migration of the low-angle <100> and <111> boundaries. According to the obtained results, the migration rate of similar boundaries in the Ni3Al intermetallide is much lower than in Ni (approximately three times at 1700 K). The reason for this is mainly the additional energy expenditure for the formation of a disordered area in Ni3Al behind the migrating boundary. Due to the relatively low mobility of the boundaries in Ni3Al, the contribution of diffusion displacements of atoms in the process of boundary migration is higher than in Ni.