Fig. 1. (a) Orientation map of the heterogeneous ZK60 sample, (b) high magnification image of the area marked by white dotted box in (a), (c) KAM map of (b), (d) pole figures of the whole data set, (e) orientation map of the overall DRXed grains containing the fine equiaxed grains and coarse row stacked grains, (f) orientation map of long elongated grains, IPFs of (g) the whole DRXed grain set, (h) the coarse DRXed grain subset, (i) the fine DRXed grain subset and (j) the long elongated unDRXed grain subset, respectively. The orientation map (a), (e), (f), and IPFs (g-j) are constructed referring to ED. The schematic diagrams at the bottom of (a) show the observation plane, extrusion direction and tensile direction.

Fig. 2. (a) IPF showing the bimodal grain size distribution, (b) the grain size statistics, (c) the {1$\bar{2}$12} <$\bar{1}$2$\bar{1}$3> macro Schmidt factor distribution, (d) Schmidt factor value statistics. The cross section is characterized by EBSD, and ED is indicated in (a).

Fig. 3. EBSD characterization of the solutionized ZK60 alloy without extrusion, (a) IPF showing homogeneous equiaxed grains, (b) grain size statistics indicating uniform grain size distribution.

Fig. 4. TEM images of the peak-aged ZK60 alloy after the extrusion, showing rod shaped precipitates viewed in the directions of (a) <01$\bar{1}$0> α and (c) <0001> α zone axis. (b) and (d) in the insets are the corresponding selected area electron diffraction patterns. (e) rod length and (f) rod diameter size distribution histograms of the nanoscale precipitates.

Fig. 5. TEM images of the peak-aged ZK60 alloy without extrusion, showing rod shaped precipitates viewed in the directions of (a) <01$\bar{1}$0>α and (c) <0001> α zone axis. (b) and (d) in the insets are the corresponding selected area electron diffraction patterns. (e) rod length and (f) rod diameter size distribution histograms of the nanoscale precipitates.

Fig. 6. Mechanical properties of the homogeneous and heterogeneous ZK60 alloys, (a) age-strengthening response as a function of ageing time, (b) typical tensile engineering stress-strain curves corresponding to the dots marked in (a), (c) yield strength vs. total elongation of our ZK60 alloy and other reported Mg-Zn based alloys, (d) work hardening rates and true stress-strain curves corresponding to the dots marked in (a).

Fig. 7. TEM images of the grain observed using diffracting vectors of (a, b) g

Fig. 8. Analysis of the dislocation structure in the local region A of the grain. (a) a set of two-beam bright-field high magnification images, (b) a sketch showing the identification of <a> and <c + a> dislocations in the examined area.

Fig. 9. Analysis of the dislocation structure in the local region B of the grain. (a) two-beam bright-field high magnification image, (b) magnified image of the marked area in (a), (c) a sketch showing the identification of pyramidal < a > mixed dislocations in the examined area.

Fig. 10. Analysis of the dislocation structure in the local region C of the grain. (a) two-beam bright-field images, and (b) magnified two-beam bright-field image of (a), and (c) weak-beam dark-field image, (d) a sketch showing the identification of < a > dislocations in the examined area.

Fig. 11. Analysis of the dislocation structure in the local region D of the grain. (a) two-beam bright-field images and (b) weak-beam dark-field images, (c) a sketch showing the identification of pyramidal < a > mixed dislocations in the examined area.