## 3 Results
### Microstructural Analysis by SEM of the Consolidated Samples  
Figure 14a,b exhibits the electron micrographs corresponding to the sintered specimen Al-5 Cr. In this case, Figure 14a was obtained by secondary electron image mode and Figure 14b was attained by backscattered electron image mode. These micrographs display bright precipitates with a flake morphology uniformly dispersed in Al matrix. As shown in the Al-Cr binary alloy phase diagram, these compounds appear as a result of Cr's very low solid solubility in Al. Figure 14c,d exhibits the precipitate size distributions considering its length and width. Derived from these histograms, the mean of precipitate width is 1.7 \(\upmu\)m and the mean of precipitate length is 6.5 \(\upmu\)m.  
Figure 14: (**a**) and (**b**) Scanning electron micrographs of the sample Al-5 Cr in consolidated state, (**c**) precipitate size length distribution and (**d**) precipitate width distribution. Figure 15a shows the studied surface of Al-5 Cr consolidated piece, the X-ray mappings of Al and Cr corresponding to this area, as demonstrated in the subsections (b) and (c) of this figure in a respective way. Element's mappings denote a homogeneous distribution of both Al, and Cr among the whole surface analyzed. Figure 15c shows X-ray signals emitted from Cr element. These signals are grouped to form small \"clusters\", this behavior is associated with the formation of Cr-rich precipitates in these small regions. In addition, part (b) of the same illustration indicate that Al is uniformly dispersed in the whole analyzed surface, it is worth noting that black holes can be seen spread throughout the Al matrix; it is essential to point out that these holes are accompanied by a Cr-rich precipitate. The punctual chemical analyses performed on the bright precipitates revealed an approximate composition of 65 at. % Cr and 35 at. % Al. Based on the system's binary alloy phase diagram Al-Cr, this composition corresponds to the Cr\({}_{2}\)Al phase which possesses a pearson symbol t6 with a prototype phase of the kind MoSi\({}_{2}\). Figure 16a,b exhibits the SEM micrographs corresponding to the sintered exemplar Al-7.5 Cr. In this case, Figure 16a was obtained by secondary electron image mode and Figure 16b was attained by backscattered electron image mode. These micrographs display bright precipitates with an irregular morphology with round borders uniformly distributed in Al matrix. However, the volume fraction of porosity increased considerably. The precipitation of these compounds is consistent with the binary alloy Al-Cr phase diagram, since Cr exhibits a low solubility in Al. Moreover, Figure 16c displays the precipitate size distribution of Al-Cry precipitates on the Al matrix, where is observed that most of the precipitates have sizes within the interval from 3.9 to 6 \(\upmu\)m, with a mean size of 4.3 \(\upmu\)m.  
Figure 17a presents the analyzed surface of Al-7.5 Cr consolidated specimen, the X-ray mappings of Al and Cr corresponding to this area, are shown in (b) and (c) of this figure, respectively. The elements' mappings prove a homogeneous dispersion of both Al and Cr among the whole surface analyzed. Figure 17c shows X-ray signals emitted from Cr element. These signals are grouped to form small \"clusters\", this behavior is associated with the formation of Cr-rich precipitates in these small regions. In addition, subsection (b) of Figure 17 exhibits that Al is uniformly distributed in the total analyzed surface, it is important to note that dark holes are observed also dispersed in Aluminum, it is essential to denote that in the places where these holes are detected, there is a precipitate rich in Cr  
Figure 16: (**a**) and (**b**) Scanning electron micrographs of the sample Al-7.5 Cr in consolidated state, (c) precipitate size distribution. Figure 15: (**a**) Microstructure of Al-5 Cr consolidated sample, chemical mappings of (**b**) Al and (**c**) Cr. The punctual EDS chemical analyses carried out on the bright precipitates indicate an approximate composition of 91.5 at.