Investigation of interfacial feature and interactional behavior of {11(2)over-bar2} twin in deformed titanium

Due to the limited availability of slip systems, deformation twins have to play an additional role to accommodate strain in developing plastic deformation and undoubtedly influence the mechanical properties of materials with hexagonal structure. Therefore, understanding the interfacial characteristic of deformation twin and interaction behavior between different twin variants during plastic deformation is crucial to microstructural design, processing and application of hexagonal close-packed (hcp) materials. In the present study, {11 (2) over bar2} twinning behavior in deformed titanium, with an emphasis on the misorientation across {11 (2) over bar2} twinning boundary and the interaction between two {11 (2) over bar2} twin variants sharing the same [10 (1) over bar0] zone axis, is investigated by a combination of electron back-scatter diffraction (EBSD) and transmission electron microscopy (TEM) techniques. The results reveal that the actual value of misorientation across {11 (2) over bar2} twinning boundary is not always equal to the theoretical one. Also, a distinctive phenomenon of one twin penetrating into the interior of the other twin, which is not observed when two {10 (1) over bar2} twins encounter to each other, is discovered when the interaction between two {11 (2) over bar2}twins takes place. Accordingly, the possible mechanisms behind such phenomena are proposed and discussed. These findings are expected to provide an insight into understanding the twinning behavior in hcp metals. (c) 2019 Elsevier B.V. All rights reserved.