Computed structure of grain boundaries compared with TEM observations

Abstract

Employing computer simulation techniques several studies of the relaxation of atoms in coincidence type grain boundaries have been performed in recent years. Often it is difficult to obtain a clear representation of the relaxed boundary structure, especially in the case of small atomic displacements. In this paper a method of representing the relaxed grain boundary structure is described using a Fourier analysis of the atomic configuration after relaxation. Computer experiments were carried out on Σ = 19, 46.8°/[111] in Al. Next, results obtained from computer experiments dealing with the interaction between He and a tilt grain boundary in Mo are presented. Direct motivation for this study stems from the transmission electron microscopic observation of helium trapping at a set of [100] edge dislocations defining a low angle tilt boundary in Mo.