High-resolution transmission electron microscopy study of a low-angle boundary in plastically deformed Ti3SiC2

The dislocation structure of a typical low-angle boundary associated with a kink band in a sample of Ti3SiC2 deformed at room temperature was studied by high-resolution transmission electron microscopy. The boundary had both tilt and twist components. To account for both, the boundary was interprete d to be composed of parallel alternating mixed perfect dislocations with tw o different Burgers vectors lying in the basal plane at an angle of 120 deg rees relative to one another. The boundary twist was provided by having an excess of one type of dislocation. This hitherto unreported structure of a low-angle boundary is attributed to the fact that all dislocations are conf ined to the basal planes.