Deformation twins in thin foils of the polycrystalline a-phase were viewed along the [1¯2▪0] direction, using high-resolution electron microscopy. The elements of the twinning mode were (10▪2) and [10▪¯1]. The interface consisted of steps which separated perfect and defective segments. The perfect areas exhibited a corrugated structure on the boundary plane, while the defective areas had a dislocation nature which was associated with steps of various heights. The shorter steps corresponded to the so-called b2/2 twinning dislocation. Models for the relaxed structures of both the perfect boundary and the b2/2 twinning dislocation were constructed by using many-body potential calculations that were based upon 2 different potentials. The resultant atomic positions were used to simulate high-resolution electron microscopic images. The latter were compared with the observed ones, and the results showed that one of the potentials led to better image-matching for the perfect twin boundary.

Structural Characteristics of Twin Boundaries in Deformed Polycrystalline Zirconium. P.Komninou, G.Nouet, T.Kehagias, A.Serra, T.Karakostas: Materials Science Forum, 1999, 294-296, 365-8