## 2 Materials and Methods  
The Inconel 718 nickel-based alloy was selected for the study, which is widely employed in jet engines thanks to its outstanding corrosion resistance and good mechanical properties at high temperatures. There are three reasons for the material choice: the availability of the materials both in forged and powder format, the amount of the literature for consultation, and the high interest in the DED-LB repair and hybrid manufacture of Inconel 718 gas turbine/jet engine components. Additionally, the Inconel 718 is an expensive material, in which any saving results in reducing the process' expenses, as well as lowering the environmental impact of the manufacturing process. The base material employed to manufacture the specimens was a 60 mm-diameter and 20 mm-high cylindrical disk obtained from wrought Inconel 718. The filler material for DED-LB in the specimen manufacture was a gas-atomized Inconel 718 powder. The upper and lower faces of the base-forged material were ground to ensure substrate flatness and cleaned with acetone to remove any coolant residues that could have affected the DED-LB tests. Both the base alloy for the substrate and DED-LB overlay were analyzed by spark emission spectrometry using the internal method based on ASTM E1086 [26]. As mentioned below, DED-LB layers were used to build the specimens up to a thickness of 12 mm. The chemical composition of the deposited material was measured in a cylinder extracted at about half the height of the deposited layer, in the same position as the SPTs in the deposited area. The chemical composition of the Ni-base powder was also analyzed by inductively coupled plasma emission spectrometry, which is an internal method based on the UNE-EN 10361 standard [27]. The carbon content was measured using an automatic infrared analyzer and the followed procedure was based on ASTM E1019 [28] for the three material conditions: forged, DED-LB, and powder material. After sticking the dispersed powder particles onto a flat surface, the powder was characterized by field emission scanning electron microscopy (FESEM) with a ZEIS Ultra Plus microscope (Carl Zeiss AG, Oberkochen, Germany). The particle size distribution of the powder was determined using the ImageJ (1.53 e) software. Circularity was defined as \(4\pi A/P\), where \(A\) and \(P\) are the area and the perimeter of the powder particle, respectively. An energy-dispersive X-ray (EDX) spectroscopy analysis was conducted with a field emission scanning electron microscope to determine the mapping of alloying elements. Prior to manufacturing the hybrid specimens, DED-LB process adjustment tests were performed in a five-axis laser center coupled with a 1 kW continuous maximum power laser from Coherent (Saxonburg, PA, USA). An in-house manufactured coaxial nozzle was employed (Figure 1) and argon with 99.99% purity was employed as the drag and protective gas with 5 L/min and 15 L/min flow rates, respectively. The focal plane was situated at a 15 mm distance from the nozzle tip, where the laser was focused at a 1.5 mm circular spot. Powder was supplied into the nozzle through a Sulzer Metco Twin 10c gravimetric powder feeder (Pfaffikon, Switzerland) with heated hoppers, which were warmed up to 60 \({}^{\circ}\)C prior to the tests to remove any moisture from the powder. The powder feeder was calibrated for the selected material and the relation between the rotation speed and the feed rate was defined via Equation (1), where \(N\) is the feeder rotation speed in revolutions per minute and \(Q\) is the outcome feed rate in grams per minute:  
\[Q=0.3442\cdot N+0.1555 \tag{1}\]  
The attenuation of laser power through the employed optical systems was measured by a photodiode cell, and the laser was calibrated to provide the desired real power. Two averaging sequences were performed and in each the energy consumption was measured in ascending and descending orders throughout the power range of the laser. Therefore, four measurements, 60 s duration each, were carried out for every nominal laser power value.