## 3 Results and Discussion
### Microstructure and Microtexture Characterisation
The optical micrographs of samples C, D and E  
Figure 4: The secondary electron images (SEI) of samples (**a**) C, (**c**) D and (**e**) E and \(\alpha\)-grain boundary distribution in samples (**b**) C, (**d**) D and (**f**) E. The red arrows indicate the build orientation. showing microstructural features on a larger area of these samples can be found in [29]. The volume percentage of \(\beta\)-phase in samples C, D and E was estimated by the X-ray diffraction method in [29] as 3.6%, 6.4% and 6.5%, respectively. For detailed analysis of XRD profiles of samples C, D and E, the reader is referred to the authors' work in [PERSON] et al. [29]. The crystallographic microtexture in the form of orientation distribution maps and local grain/intragranular misorientation maps of different forms of the DMLS Ti6 Al4V(ELI) alloy is shown in Figure 5. The microtexture plays a critical role in determining the mechanical performance of Ti6 Al4V(ELI) because it impacts the activities and roles of all the slip systems in it. Figure 5: (**a**,**c**,**e**) The orientation distribution maps and (**b**,**d**,**f**) the local grain misorientation/low angle grain boundary maps in samples C, D and E, respectively. The red arrows indicate the build orientation. In Figure 5a,c, the \(\alpha\)-laths are seen to have grown from the columnar prior \(\beta\) boundaries toward the interior of the grains. However, most of these \(\alpha\)-laths within the same \(\beta\)-grain have a random orientation shown by the colour codes related to specific orientations as represented by the Inverse Pole Figure (IPF) key inserted in each of the micrographs in Figure 5a,c. Several orientations or invariants of \(\alpha\)-laths can be seen within the same prior \(\beta\) grains in samples C (Figure 5a) and samples D (Figure 5c). These different invariants are related to the \(\beta\)\(\rightarrow\)\(\alpha\) phase transformation during cooling, where twelve definite orientations of \(\alpha\)-phase can be precipitated from a single-parent \(\beta\)-grain [30; 32]. Nevertheless, a few \(\alpha\)-grains of the same elongated prior \(\beta\) grain have orientations that tend to occur more frequently than others, and this is shown by the frequent occurrence of the same colour of these \(\alpha\)-laths. Typical examples of these crystals are shown by white arrows in Figure 5a,c. This preference of certain orientations during \(\beta\)\(\rightarrow\)\(\alpha\) transformation in Ti6 Al4V is attributed to variant selection, of which further details can be found in [34]. The typical orientation map of samples E shown in Figure 5e consists of semi-equivaved and equiaxed shapes of the prior \(\beta\) grains with different colonies. Each colony consists of parallel \(\alpha\)-laths, which have the same crystallographic orientation, as depicted by the similar colour. Figure 5b,d,f shows the high-angle grain boundaries (HAGBs) represented by the black solid lines and the low-angle grain boundaries (LAGBs)/intragranular structures represented by the orange lines in samples C, D and E, respectively. The HAGBs were set as the boundaries where the misorientation angle between neighbouring laths was \(\geq 10^{\circ}\), while the LAGBs were set as those with the misorientation angle being \(<10^{\circ}\). It is clear from Figure 5b that in some areas the columnar prior \(\beta\) grain boundaries were LAGBs connecting to HAGBs from both ends. The LAGBs were also observed in samples D (Figure 5d), most of which were running across several \(\alpha\)-laths. In Figure 5f, the \(\alpha\)-laths in most colonies are seen to possess LAGBs between them and HAGBs between different colonies. Additional details on the misorientation angle distribution and proportions of LAGBs and HAGBs in samples C, D and E can be found in the authors' previous work published in [29].