APPROXIMATIONS TO THE WHIPPLE SOLUTION FOR GRAIN-BOUNDARY DIFFUSION AND AN ALGORITHM FOR THEIR AVOIDANCE

This paper concerns the Whipple model for grain boundary diffusion. In particular, it examines the various approximations that have been use d to calculate solute concentration from the equation provided by Whip ple. Included are approximations intended to permit the determination of grain boundary diffusivities from experimental data, An algorithm i s presented which avoids these approximations. It is demonstrated that the algorithm is robust in the face of moderate experimental error, a nd, unlike an alternative, can be used to minimize the impact of that error. (C) 1997 American Institute of Physics.