## 3 Results and Discussion  
### Microstructural Characterization of As-Extruded, 37% Rolled and 68% Rolled Samples  
Longitudinal, through-thickness cross-sections of the ZK60 samples for the ShAPE extruded and flattened, 37% hot-rolled, and 68% hot-rolled sheets are shown in Figure 2. In the ShAPE extruded and flattened microstructure, it was observed that the grains were equiaxed. Upon extrusion, in the case of the flattened specimens, the inverse pole figure maps of the microstructure show that twinning (blue bands in the red matrix) had occurred during the flattening process (Figure 2 inset). It should be noted that the flattening procedure was performed at room temperature. However, the microstructure maintains the majority of its texture and uniformity from [PERSON] et al. [5]. The 37% and 68% rolled plates exhibited the same equiaxed microstructure and were accompanied by bands of low diffraction contrast, resulting in non-indexed pixels. The through-thickness longitudinal EBSD scans of the sheets showed that while the as ShAPE extruded and flattened sheet has a very uniform microstructure, after a 37% reduction there are grains that have visibly grown and deviated from the as-extruded texture. Diffraction bands in Kikuchi patterns from EBSD were notably weaker lending itself unable to determine a grain orientation, which either indicates that the region has been highly deformed or that the region has very fine recrystallized grains. Deformation twinning in Mg alloys has been previously reported by numerous authors [40; 41]. The twinned grains were present in the microstructure upon ShAPE processing and flattening the plates. However, they were not seen in the as-ShAPE'd microstructure [5; 29]. This shows that they were formed due to the flattening process at room temperature, indicating that these are deformation twins. A measurement of the misorientation profile between the apparent twinned grains confirms that these grains were indeed twinned, as shown in Figure 3.  
When plotted to show orientation density, it was observed that the microstructure of the flattened plates showed that the basal planes were approximately tilted 5-10\({}^{\circ}\) away from the extrusion direction, as shown in Figure 4. As shown in Figure 4a and its corresponding pole figure in Figure 4d, the tilt of the basal plane is approximately 5-10\({}^{\circ}\) away from the extrusion direction. With the applied hot rolling and reheating treatment, the basal planes oriented themselves parallel to the rolling direction. After a 68% reduction, the grain size increased. A similar trend can be seen for transverse sections of the ZK60 samples, as shown in Figure 5. These results also indicate that despite the initial rotation being away from the rolling direction as a result of the ShAPE process, the multiple rolling passes cause texture rotation back towards the rolling direction. Figure 2: Through-thickness longitudinal EBSD orientation maps of the ShAPE extruded and flattened, 37% hot-rolled, and 68% hot-rolled ZK60 specimens in the longitudinal section. In each map, the left side was the outer diameter of the tube, while the right side was the inner diameter of the tube. Figure 4: EBSD orientation (IPF Y) maps (**a**–**c**) and their respective pole figures (**d**–**f**) of the ShAPE extruded and flattened, 37% hot-rolled, and 68% hot-rolled ZK60 specimens, respectively, in the longitudinal section. Figure 3: (**a**) Grain orientation (IPF Y) map showing the deformation twinning between two grains in the as-flattened ZK60; (**b**) Misorientation profile on an EBSD map of the as-flattened ZK60 plate. The yellow arrow in Figure 3a indicates the location and direction of the misorientation line profile.