Interactions between basal < a > dislocation and { 11(2) over bar 2 } twin boundary in HCP metal: A molecular dynamics study

For hexagonal close-packed (HCP) metals having a c/a < root 3 , basal slip is the most common slip system, and {11(2) over bar2} twinning is one of the primary plastic deformation modes when compressive stress is applied along the c-axis. In this work, molecular dynamics simulations have been applied to reveal the interaction mechanism between different basal dislocations and {11(2) over bar2} twin boundaries (TBs) in Mg, Zr and alpha-Ti. When the (0001) 13[1120] dislocation interacts with the {11(2) over bar2} TB, it is transmuted into a {11(2) over bar2}-{11(2) over bar1} double twin (DT). With increasing shear stress, the growth of the {11(2) over bar2}-{11(2) over bar1} DT is impeded by the other side of the {11(2) over bar2} TB, it transmutes into (0001)1/3<1010> dislocations and twin dislocations (TDs). Furthermore, the {11(2) over bar1} TB is capable of transforming into a {11(2) over bar2} TB and a new co-zone {11(2) over bar1} TB, which then forms a twin-twin junction (TTJ) to release stress concentration. When the (0001)1/3[2110] dislocation interacts with {11(2) over bar2} TBs, it transmuted into a I2 SFs in the twin and a TD with one-layer height on the {11(2) over bar2} TB. But the (0001)13[12(1) over bar0] dislocation would be impeded by the {11(2) over bar2} TB and couldn't be transmuted further.