## 3 Results and Discussion
### Structural and Morphological Properties of the Power Particles
#### 3.1.1 X-ray Diffraction
The atomic radius of graphite is 0.067 nm, in which the C/W and C/Mo ratios are 0.4806 and 0.4834, respectively, indicating that graphite can accommodate in the interstitial sites of the WMo metal lattice. The two-metal lattice has a bcc crystalline structure. In this type of structures, there are two types of interstitial sites: tetrahedral sites, located at \(\frac{1}{2}\), \(\frac{1}{4}\), and 0 (real space with all equivalent sites) and octahedral sites, located on the faces of the cube at \(\frac{1}{2}\), 0, and \(\frac{1}{2}\) (real space with all equivalent sites). An atom whose radius relation is greater than 0.414 is in an octahedral site [27]. For the transition elements, the metallic structure's interstitial tetrahedral sites are very small to accommodate graphite, so only the octahedral sites must be occupied [23]. At 150 h of milling, the MoWC phase remained with the largest intensity, and the WMo phase was still present at this stage of milling (see the zoomed-in image at 150 h in Figure 3). The microstructural evolution sequence of the phase against milling time was:  
\[\text{C}+\text{W}+\text{Mo}\rightarrow\text{C}+\text{WMo}\rightarrow(\text{ WMo})\text{C}\]  
Figure 3: XRD patterns of the MoWC mixture at different grinding times in a high-energy mill (1500 rpm) and a zoom between 40\({}^{\circ}\) and 41\({}^{\circ}\) of XRD patterns of the MoWC mixture at 150 h of milling. We proposed that this phase (MoWC) showed a bcc crystalline structure like MoW system; this agreed with the experimental method proposed by [PERSON] for the determination of crystalline structures of cubic type, which explains that the correct Bravais lattice can be determined following the sequence of the typical reflections associated with the cubic lattice [26] from the relation:  
\[\sin^{2}\theta=\frac{\lambda}{4a^{2}}\left(h^{2}+k^{2}+l^{2}\right) \tag{1}\]  
After calculating for the material, the sequence path of reflections for \(h^{2}+k^{2}+l^{2}\) was 2, 4, 6, 8, and 10, which corresponded to a bcc structure; the indexation of crystallographic planes was: (110), (200), (211), (220), and (310) (see Figure 3). The calculation of the lattice parameter and d-spacing was according to Equations (1)-(3) and every plane assignment for each reflection was associated with the lattice parameter/d-spacing ratio. The results are in Table 1.  
\[d=\frac{\lambda}{2\sin\theta} \tag{2}\]  
\[a=d(h^{2}+k^{2}+l^{2}) \tag{3}\]  
where \(d\) is the interplanar distance (nm), \(a\) is the lattice parameter (nm), and \(\lambda\) = 0.1540 nm. An average lattice parameter of 0.3148 nm was obtained. According to XRD results and Scherrer calculations, at 150 h of milling, the crystal size showed an average of about 40.8 nm. This indicated that the formation of the MoW alloy and the bcc structure of MoWC was only possible at the nanostructure level. The material showed a solid solution behavior at this size, and the crystallinity was of a short-range order [17; 28]. According to [PERSON] [29], there are solid solutions with several components, where the primary phase shows the majority weight percent, and the others are formed with intermediate ranges of the composition. In this case, the phase observed at 150 h was a nanostructured MoW alloy that could be considered as a secondary solid solution. This implied that these phases require very high energy for their formation. The evidence that this material had a solid solution behavior is easily observed in Sections 3.1.4 and 3.2, which will be discussed later.