## 3 Results and Discussion  
Thermodynamics calculations by the Factsage(r) software (CRCT group at Ecole Polytechnique de Montreal, Canada) developed by the CRCT group at Ecole Polytechnique de Montreal were used to design the reinforcing phase by simulating the reaction of various alloying elements with the carbon from the binder and powder. The software calculated the equilibrium phase and thermodynamics parameters for a variety of multi-component, multi-phase, and reactions. The Gibbs free energy for the formation (\(\Delta\)G\({}_{\rm{f}}\)) in Figure 2 shows the most stable carbide among the reactions between the metal elements and one mole of carbon. When using FeCrCoNiAlTiC powder, it was necessary to confirm whether titanium carbide was a thermodynamically stable carbide in the in situ reaction. The powders were mechanically alloyed and could be assumed to be completely homogenized. Laser cladding is a non-equilibrium reaction with very fast temperature changes, which melts the powder and then solidifies rapidly. Non-equilibrium phases could also be precipitated, but the most thermodynamically stable phase is preferred. As a result of the calculation, TiC was found to be the most stable phase among the alloying elements in this powder, followed by chromium carbide. In Ti-free HEA alloy, the most stable chromium carbide phase except for TiC is formed [20]. The second stable carbide phase, chromium carbide, is formed when carbon capture Ti element enough and redundant C remains [21]. Both TiC and Cr\({}_{23}\)C\({}_{6}\) are superior materials that enhance hardness and wear resistance higher than that of a stainless-steel substrate, but TiC had better wear resistance than chromium carbides [22]. Therefore, the spontaneous formation of titanium carbide instead of chromium carbide by adding Ti to multi-component alloy powders, such as HEAs, is important for the properties of the coating layer. Figure 2: Gibbs free energy for formation of carbide formation reaction between 1 mole of carbon and the metal component in HEAs powder. TIC is formed by self-propagating high-temperature synthesis (SHS) reactions with a laser heat source [23]. The laser heat source dilutes powder and substrate to form a molten metal pool. The heat input and the flow of the molten pool affect the thickness of the coating layer and the distribution of reinforcing particles. The reinforcing particles are grown or dissolved through interaction with the liquid metal moving with the molten pool flow, and the final cladding layer is formed with the solidification by cooling. In the case of gas tungsten arc process, heat transfer occurs due to conduction and convection, and the molten pool is driven due to the various effects of the electromagnetic force, buoyancy force, arc drag force, and surface tension [24]. In the arc process, since the reinforcing particles were not mixed in the depth direction, and the flow at the surface was governed by the driving forces, it was difficult to distribute the reinforcing particles homogeneously in the depth direction [8; 25]. The laser process had a higher energy density and faster process than the arc process, so the laser process could be a favorable environment for transporting and dispersing reinforcing particles in the depth direction. The coating thickness in Table 2 shows the average value and standard deviation of a total of 10 values, 5 each for the peak measured at the center of the pass passed by the laser and the valley where the thinnest coating layer is formed between the passes. Effective heat input and coating thickness provide useful information about the relationship between process parameters and clad quality. Effective heat input (\(E_{a}\)) was calculated by the below equation: \(E_{a}=P/V\)D where \(P\) is laser power, \(V\) is scan speed of laser, \(D\) is laser spot diameter. Since constants were used except for the laser power, the effective heat input in this study was proportional to the laser power.