Phase field study the effects of interfacial energy anisotropy on the thermal migration of voids

Abstract

While it is well known that inclusions (gaseous, fluid or solid) in a solid matrix would migrate under the driving force of a temperature gradient and the inclusion morphology is strongly affected by the material anisotropy, the influence of material anisotropy on the thermal migration of inclusions is still not clear. Via including an interfacial energy anisotropy into a phase field model of void migration driven by a temperature gradient, here we show that the interfacial energy anisotropy brings nontrivial effects on the void migration behavior. On the one hand, the void deformation during migration depends on the orientation of the anisotropy. On the other hand, a transverse velocity of the void appears if there is a misalignment between the symmetry axis of the anisotropy and the global temperature gradient direction. Such a transverse motion is due to the fact that the thermal diffusion flow becomes asymmetrically distributed around the void surface if the temperature gradient direction does not coincide with the symmetry axis of the anisotropy. The effects of the void size, the anisotropy parameter, and the thermal conductivity difference between the void and the matrix are discussed.