Microscopic phase-field simulation for nucleation incubation time of Ni_(75)Al_xV_(25-x)alloy

摘要

With the microscopic phase-field dynamic model, the effects of temperature and concentration on the nucleation incubation time of Ni 75AlxV 25-xalloy were studied and the relation between the incubation time and precipitation mechanism was investigated by using the atomic occupation probability picture and average order parameter curve. The simulation results demonstrate that there exists the incubation time for different precipitation mechanisms, such as non-classical nucleation, the mixed style of non-classical nucleation and spinodal decomposition, and spinodal ordering; and the incubation time shortens in turn for the three kinds of mechanisms. With the increase of Al content of Ni 75AlxV 25-xalloy, the incubation time of L12 phases shortens continuously and that of D0 22phases is prolonged. The effects of temperature on the incubation time of L12 and D0 22phases are accordant, i.e. the incubation time is greatly prolonged with the temperature rising.