材料期刊网

In nanocrystalline (nc) materials, the misfit of lattice structures at the junctions of grain boundaries (GBs) generally increases local stresses that can be released by GB sliding. In this article, the sliding behaviors of the ordered Sigma = 3 (111) [110] GB (twin) and Sigma = 11(113) [110]GB in nc palladium have been investigated by means of high-resolution transmission electron microscopy observations and molecular statics calculations. It is found that the twin boundary (TB) can release either large stresses by sliding with a DSC-lattice vector of 1/6 [112] or small stresses by sliding over an imperfect vector. The observed Sigma = 11 GB image is exactly symmetrical from which we can clearly identify no GB sliding along the [332] direction, but we cannot determine a sliding component along the [110] direction. The image simulations indicate that the latter is experimentally unidentifiabl e.