The first systematic investigation was made here of the pressure and orientation dependences of grain boundary diffusion. The diffusion of Zn was measured at 553K, in the B-kinetic regime, using various sets of bicrystals and pressures of up to 1.2GPa. Symmetrical <001>, <011> and <111> tilt boundaries were studied (tables 27 to 29), with tilt angles that corresponded to a low coincidence lattice-site parameter. The Zn depth profiles were measured by means of electron probe micro-analysis, and were analyzed by using the Whipple equation. The orientation dependence of the diffusivity went through minima, for the high-coincidence grain boundaries, under all of the applied pressures. The activation volume ranged from 26 to 47% of the atomic volume of Al, and exhibited slight maxima for the high-coincidence grain boundaries.

P.Klugkist, A.N.Aleshin, W.Lojkowski, L.S.Shvindlerman, W.Gust, E.J.Mittemeijer: Acta Materialia, 2001, 49[15], 2941-9