Figure 1

The unit cell used for computation of dislocation core structures. The unit cell contains a dislocation dipole formed of two screw dislocations, both with the easy core. The unit cell is outlined in black. The gray lines indicate the stacking of the cells. The dashed line indicates the trace of the plane of atoms depicted in Fig. 4.Reuse & Permissions

Figure 2

(Color online) Dislocation core structures predicted by density-functional theory. The core displacements are indicated using differential displacement maps (see text). The contours indicate the regions of the unit cell considered to be within a dislocation core based on continuum linear elasticity theory. (a) The structure of the dislocation cores for the ${\text{Ti}}_{25}{\text{V}}_{75}$ alloy. The ideal shear stress is 4.3 GPa indicated by the contours. (b) The core structures for a ${\text{Ti}}_{80}{\text{V}}_{20}$ alloy with ideal strength of 600 MPa (indicated by the contours).Reuse & Permissions

Figure 3

(Color online) A nominally (111) view of the atomic scale structures predicted for (a) ${\text{Ti}}_{25}{\text{V}}_{75}$,(b) ${\text{Ti}}_{80}{\text{V}}_{20}$, and (c) view of (b) oriented as in Figs. 1, 2 showing the positions of the dislocations (black squares). The plane of the “nanodisturbance,” $\left(1\overline{1}0\right)$, is indicated by arrows. The four black lines are parallel to one another and aligned along the columns of atoms going into the page in panels (a) and (b). There is a slight lateral displacement of the two lines in the lower part of the figure relative to those in the upper part that arises from the nanodisturbance. In the crystal, (111) planes are stepped. These figures were created by considering only the positions of the [111] columns within (111). A three-dimensional sphere was plotted at the position of the column of atoms. This structure was then viewed as shown to reveal the displacements of the columns of atoms.Reuse & Permissions

Figure 4

(Color online) The predicted atomic scale structure viewed along (nominally) $\left[0\overline{1}1\right]$ for (a) ${\text{Ti}}_{25}{\text{V}}_{75}$ and (b) ${\text{Ti}}_{90}{\text{V}}_{10}$ alloys. In (a), the columns show local bending. In (b), the bending is resolved into faults similar to those observed in gum metal (Ref. 5).Reuse & Permissions