EFFECT OF SURFACE-DIFFUSION ON THE CREEP OF THIN-FILMS AND SINTERED ARRAYS OF PARTICLES

An analysis is presented that illustrates the effect of surface diffusion on the creep of a uniform, sintered array of cylinders. The analysis is also appropriate for describing the creep of thin films bonded to substrates when there is no interfacial diffusion. The first part of the paper presents an analytical solution which can be obtained when it is assumed that a constant flux of matter out of the grain boundary is maintained. This solution illustrates the important physical phenomenon behind the problem in that a finite surface diffusivity causes a back stress to be developed owing to the enhanced surface curvatures in the region of the grain boundary. In the latter portion of the paper, this analytical solution is used to generate numerical solutions for more practical boundary conditions, and to illustrate the effects of finite boundary lengths.