Computer simulation of grain-boundary diffusion creep

Under externally applied stress, polycrystalline materials may deform as a result of matter diffusing from grain boundaries in compression to those in relative tension. We model the behaviour of a general structure under several different boundary conditions and show how the stress function along each grain boundary may be obtained by solving a system of linear equations. We further show how knowledge of the stresses enables us to predict the position of the grain boundaries after a small time-step deltat and use this to simulate changes in the grain structure over a finite time interval. Our simulations indicate that grain-size distribution is of importance with regard to the onset of buckling. We are also able to track the movement of individual grains during deformation and our results show that, in an irregular grain structure, diffusion creep may cause significant grain rotation. (C) 2002 Acta Materialia, Inc. Published by Elsevier Science Ltd. All rights reserved.