## 2 Research Methodology
### Simulation Results  
The simulation results depicting displacement deformation of the turbine pump impeller model under different laser power and scanning speed parameters are illustrated in Figure 3. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Length (mm)** & **Width (mm)** & **Height (mm)** & **Blade Length (mm)** \\ \hline
30.74 & 30.74 & 23.23 & 10.81 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Geometric model parameters. \begin{table}
\begin{tabular}{c c} \hline \hline
**Property** & **Value** \\ \hline Yield strength & 1100 Mpa \\ Elastic Mmodulus & 110 Gpa \\ Poisson ratio & 0.34 \\ Density & 4510 kg/m\({}^{3}\) \\ Liquid thermal conductivity & 7.9555 W/m-K \\ Specific heat & 0.72 J/(g\({}^{\circ}\)C) \\ Coefficient of linear expansion & 8.6 x 10\({}^{-6}\) \\ Solidus temperature & 1550 \({}^{\circ}\)C \\ Liquidus temperature & 1630 \({}^{\circ}\)C \\ Surface tension coefficient & 1.882 \\ Latent heat of fusion & 285 kJ/kg \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Material properties of TC4. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Value** \\ \hline Laser Thickness & 30 \(\upmu\)m \\ Hatch Spacing & 140 \(\upmu\)m \\ Baseplate Temperature & 80 \({}^{\circ}\)C \\ Laser Beam Diameter & 100 \(\upmu\)m \\ Slicing Stripe Width & 10 mm \\ Starting Layer Angle & 57\({}^{\circ}\) \\ Layer Rotation Angle & 67\({}^{\circ}\) \\ Minimum Overhang Angle & 45\({}^{\circ}\) \\ Support Factor of Safety Coefficient & 1 \\ Support Yield Strength Ratio & 0.4375 \\ Support Strain Threshold & 10\% \\ Part Strain Threshold & 20\% \\ Strain Warning Factor & 0.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Manufacturing parameters in the simulation [34]. At a power of 150 W, the maximum displacement deformation is concentrated at the edge of the turbine pump impeller's base, as shown in Figure 3. This phenomenon is mainly attributed to the larger cross-sectional area of the base, which requires the longest time for each layer to be processed. Consequently, during the base processing, the powder needs to absorb a higher amount of laser energy. Simultaneously, since the base edge is the first to be scanned in that layer, strong heat accumulation occurs due to the time effect. Under the influence of this heat accumulation effect, significant thermal deformation is observed in the base. As the scanning speed increases, the displacement deformation of the part gradually diminishes, and the deformation size exhibits an approximate linear relationship with scanning speed, as shown in Figure 4. This is primarily because, with constant power, an increase in scanning speed leads to reduced interaction time between the laser and the material. As a result, the material cannot absorb sufficient laser energy, causing the thermal effect in the melt pool to gradually decrease. Consequently, the thermal deformation of the part induced by this thermal effect also reduces accordingly. Figure 4: Effect of scanning speed on deformation. Figure 3: Simulation results of displacement deformation at different scanning speeds for laser power of 150 W.  
However, when the scanning speed is 1000 mm/s, with an increase in laser power, as depicted in Figures 5 and 6, the thermal deformation of the part gradually increases, but the rate of deformation growth diminishes. Under constant scanning speed, raising the laser power enables the material to absorb more laser energy per unit time. Consequently, the thermal effect in the melt pool strengthens progressively, leading to a gradual increase in thermal deformation of the part caused by the thermal effect in the melt pool. As both laser power and scanning speed can influence thermal deformation, we obtain the relationship diagram between laser power, scanning speed, and thermal deformation, as shown in Figure 7. Due to the combined effect of laser power and scanning speed, the part's deformation exhibits nonlinear variation.