Fig. 1. (a) Low-magnification HAADF-STEM image showing the 18R/Mg and 14 H/Mg coherent and semi-coherent (SC) interface. (b) Atomic-resolution HAADF-STEM image showing the complex 18R/Mg interfaces containing 54R in the near-equilibrium Mg97Zn1Y2 alloy. b1e, b2e and b3e are defined to be the edge component of b1, b2 and b3 dislocations, which are illustrated by open rectangles and white arrows. Two dislocation arrays in the 54R/Mg or 54R/18R interfaces result in the small tilt degree along the interfaces. The images were recorded along [2$\bar{1}\bar{1}$0]α zone axis.

Fig. 2. (a) Forces on dislocation bq and solute atom due to stress field of dislocation bp. (b) Possible arrangement of b1, b2 and b3 dislocations responsible for transformation from 18R/Mg SC interface into 54R. (c) Glide force per unit length between neighboring dislocations, such as ${{F}_{11}}\left( x,3{{y}_{0}} \right)$, ${{F}_{22}}\left( x,{{y}_{0}} \right)$, ${{F}_{23}}\left( x,{{y}_{0}} \right)$, and their edge or screw components, like ${{f}_{23,\text{e}}}\left( x,{{y}_{0}} \right)$ and ${{f}_{23,\text{s}}}\left( x,{{y}_{0}} \right)$. (d) Force considered for the b2 and b3 walls with unlimited length acting on b1 dislocation array with length of 3ny0 expressed as ${{F}_{\omega }}=2n\sum\limits_{k=-\infty}^{+\infty}\,{{f}_{12}}\left( \omega ,\left( 3k+1 \right){{y}_{0}} \right)$, and the roles of free energy on the equilibrium width ω contributed by the interaction force. The value of x and ω is expressed in units of y0, while the values of force and free energy are expressed in units of $G{{b}^{2}}/(2\pi {{y}_{0}})$ and $G{{b}^{2}}/(2\pi )$, respectively.

Fig. 3. Atomic-resolution HAADF-STEM images viewed along [2$\bar{1}\bar{1}$0]α zone axis, showing the 14 H/Mg interfaces (a) approximately parallel to (01$\bar{1}$0) plane and (c) not parallel to (01$\bar{1}$0) plane. (b) Intensity profiles of the HAADF image in rectangle in (a).

Fig. 4. Glide force per unit length acting along x zone between neighboring dislocations in 14 H/Mg interface and between their edge or screw components, such as ${{F}_{45}}\left( x,{{y}_{0}} \right)$, ${{f}_{45,\text{e}}}\left( x,{{y}_{0}} \right)$ and ${{f}_{45,\text{s}}}\left( x,{{y}_{0}} \right)$. Glide force per unit length ${{F}_{I,x}}$ acting along x zone between b4 dislocations and solute Zn/Y atoms in the tensile stress region, which can cause volume increase $\text{ }\Delta\text{ }V={{b}_{\text{e}}}{{y}_{0}}l$.