## 3 Results  
### Microstructural Analysis  
Figure 5a-d present the CLSM images of the M100 and M290 samples. The as-built M100 and M290 samples exhibit laser-melted tracks formed via an alternating 67\({}^{\circ}\) filling strategy. The widths of the tracks in the M100 and M290 samples are \(\sim\)40-70 and 80-120 \(\upmu\)m, respectively, corresponding to the hatching distances (which are related to the laser spot sizes). After heating, the laser-melted tracks are no longer observed, but the GBs are clearly observed. Figure 6a-d illustrate the SEM images of the M100 and M290 samples. The as-built samples display different layers, with several containing cellular dendrites and others featuring columnar structures due to the alternating 67\({}^{\circ}\) filling strategy. In contrast, the heated M100 and M290 samples exhibit columnar precipitates along their GBs, and the difference in the precipitate sizes of the two samples is negligible. \begin{table}
\begin{tabular}{c c c c c c c c} \hline
**Alloy** & **Co** & **Cr** & **Mo** & **Si** & **Mn** & **Fe** & **C** & **Ni** \\ \hline MP1 & 60–65 & 26–30 & 5–7 & \(<\)1.0 & \(<\)1.0 & \(<\)0.75 & \(<\)0.16 & \(<\)0.1 \\ \hline \end{tabular}
\end{table} 
Table 1: Chemical composition of the Co–Cr–Mo alloy powder in units of mass (%). Figure 6c,d and Table 2 present the SEM images and the results of the EDS point analyses of the heated M100 and M290 samples. The point analyses of the matrices and precipitates of the samples were performed at three different locations on the samples. In the M100 and M290 samples, the contents of Co are higher in the matrices compared to those of the samples. The results of the EDS point analyses of the heated M100 and M290 samples are shown in Table 2. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Matrix** & & & & & & & & \\ **(mass.\%)** & **Co** & **Cr** & **Mo** & **C** & **(mass.\%)** & **Co** & **Cr** & **Mo** & **C** \\ \hline *1 & 63.27 & 28.45 & 6.41 & 1.87 & *7 & 47.01 & 34.29 & 12.65 & 6.05 \\ *2 & 63.05 & 28.29 & 6.54 & 2.11 & *8 & 39.61 & 37.82 & 14.61 & 7.69 \\ *3 & 63.16 & 28.53 & 6.47 & 1.85 & *9 & 37.99 & 37.67 & 17.71 & 6.62 \\ *4 & 63.49 & 28.2 & 6.44 & 1.87 & *10 & 43.7 & 35.48 & 14.08 & 6.74 \\ *5 & 63.01 & 28.63 & 6.64 & 1.72 & *11 & 45.68 & 34.42 & 12.57 & 6.33 \\ *6 & 63.26 & 28.33 & 6.5 & 1.85 & *12 & 45.94 & 35.4 & 12.29 & 6.36 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Co, Cr, Mo, and C contents (mass%) of the heated samples were determined using EDS. The analyzed locations are shown in Figure 6c,d as asterisks. Figure 5: Specim microstructures. CLSM images of as-built (**a**) M100, (**b**) M290 heated, (**c**) M100, and (**d**) M290 samples. Figure 6: SEM images of as-built (**a**) M100, (**b**) M290 heated, (**c**) M100, and (**d**) M290 samples. (**c,d**) The asterisks indicate the analyzed locations of Co, Cr, Mo, and C contents (mass.%) determined using EDS, as shown in Table 2.  
in the precipitates. Conversely, the C, Cr, and Mo contents are higher in the precipitates than those in the matrices, indicating the formation of carbide (M\({}_{23}\)C\({}_{6}\)) precipitates [7]. Figure 7 shows the XRD patterns of the M100 and M290 samples. The observed peaks correspond to the FCC \(\gamma\)-Co phase. As-built M290 exhibits a strong \(\gamma\) (200) orientation, indicating the presence of a \(\{200\}\)-texture. Figure 8 plots the GBs, IPFs, phases, and KAM maps (transverse to build directions) as measured using EBSD. Both as-built samples exhibit large fractions of low-angle boundaries (LABs; \(\theta<15^{\circ}\)), high-KAM regions (green areas), and small fractions of \(\Sigma\)3 twin boundaries. The LAB fraction and high-KAM regions in the M100 sample are larger than those in the M290 sample. In contrast, the heated samples display equiaxed grains with multiple \(\Sigma\)3 twin boundaries and drastically reduced LAB fractions.