## 2 Materials and Methods
Figure 1: (**a**) Solidworks (Dassault Systèmes, Waltham, Québec, Canada) drawing of tensile samples manufactured along the \(0^{\circ}\)XZ (blue), \(0^{\circ}\)Xr (red), \(45^{\circ}\) (green) and \(90^{\circ}\)Z (yellow) directions and of bars grown along the same directions; (**b**) skin-core scan strategy where \(\theta\) is \(56.5^{\circ}\) and the orange and red arrows indicate the laser scans directions. Figure 2: Temperature–time curves related to the heat treatment (\(704\,^{\circ}\)C/\(120^{\prime}\), \(740\,^{\circ}\)C/\(130^{\prime}\) and \(1050\,^{\circ}\)C/\(60^{\prime}\)) studied in the present work. After the heat treatments, a set of samples for each batch (Figure 1a) was sandblasted (SB) through a glass micro-sphere characterized by diameters between 200 and 300 \(\upmu\)m. The process was performed manually with a distance of 300 mm from the sample surface and a pressure of 7 MPa. For a better understanding, all sandblasted samples will be called SB, while those characterized by an \"as fabricated\" surface will be called no-SB. Before and after the sandblasting process, the surface roughness was measured through an optical 3D profilometer ([PERSON], Leicester, UK). To evaluate the mechanical properties of the both SB and no-SB samples after the different heat treatments, the tensile tests were performed at room temperature with a Zwick/Roell Z100 (ZwickRoell, Einsingen, Germany) machine using a strain rate of 0.0167 s\({}^{-1}\). Three tensile samples were tested for each direction in SB and no-SB conditions, respectively. Vickers microhardness measurements were performed using both 500 gf (HV\({}_{0.5}\)) and 100 gf (HV\({}_{0.1}\)) loads and a 15 s indentation time according to the UNI EN ISO 6507-1:2018 standard specification. In the first case, 500 gf was used to evaluate the Vickers microhardness of all samples and bars. Each HV\({}_{0.5}\) value was obtained as an average of nine measurements arranged within a 3 \(\times\) 3 matrix where indentations were spaced 1 mm from one another (Figure 3a). On the other hand, 100 gf of load was used to evaluate the microhardness of the \(\alpha\)-colonies, \(\alpha\)-laths arranged in a basetweave structure, and \(\alpha\)\({}_{\text{GB}}\) (Grain Boundary). Finally, three microhardness profiles (Figure 3b) were performed along on the cross-sections of the 90\({}^{\circ}\)z-samples heat-treated at 704, 740 and 1050 \({}^{\circ}\)C to analyze the effects induced by the sandblasting process on the surface of the SB samples. Each profile was formed by 15 indentations that were 500 \(\upmu\)m apart, except for the 2 nd from the 1 st and 3 rd and the 14 th from the 13 th and 15 th, which were spaced 250 \(\upmu\)m apart. These chosen distances satisfy the following relationship: \(\delta>2d_{m}\), where \(\delta\) and \(d\) are the distance between two successive indentations and the average value of the indentation's diagonal, respectively. The heat-treated microstructures and the effects induced by the sandblasting process on the sample surface were analyzed through the DMi8 Leica optical microscope (Leica, Wetzlar, Germany) and the SEM Nova NanoSEM 450-FEI (ThermoFisher, Hillsboro, OR, USA) in parallel (xy plane, \"\(\odot\) Build direction\") and perpendicular (xz plane, \"\(\dagger\) Build direction\") directions to the build platform for 0\({}^{\circ}\)xZ-, 0\({}^{\circ}\)x\({}_{\text{Y}}\)-, 45\({}^{\circ}\)- and 90\({}^{\circ}\)z-samples. The thickness of \(\alpha\)-laths and columnar \(\beta\)-grains was measured as reported by [PERSON] et al. [43] and  
Figure 3: (**a**) Matrix of 3 \(\times\) 3 indentations where d is 1 mm of space between two adjacent indentations; (**b**) Vickers microhardness profiles performed on cross-section of the heat-treated 90\({}^{\circ}\)z-samples after and before the sandblasting process. Each profile is separated by \(\delta\). [PERSON] et al. [44], respectively.