# Al-Fe-Ni Metallic Glasses via Mechanical Alloying and Its Consolidation
## 3 Results and Discussion
mentioned that the mechanical properties of Al-based bulk amorphous alloys can be enhanced in cases where nanometer-sized face-centered cubic Al (fcc-Al) precipitates homogeneously in the amorphous matrix [11]. Therefore, as-milled powders were sintered at different temperature of 450, 500 and 600 \({}^{\circ}\)C. Figure 9 shows the fracture surface of the Al\({}_{82}\)Fe\({}_{14}\)Ni\({}_{4}\) sintered samples after the compression test. The fracture surfaces of the samples sintered at 450 and 500 \({}^{\circ}\)C exhibited a clean surface with average grain sizes of about \(\sim\)10 \(\upmu\)m. The specimen broke along the compression direction, and the fracture surface displayed a decohesive-like rupture [19] and inter-granular crack propagation. However, the trans-particle fracture mechanism observed in Figure 9b indicates the efficiency of the sintering condition. The density and compressive strength values of the compacted samples increased with the increasing sintering temperature, as seen in Table 4. The highest compressive strength obtained for sample sintered at 600 \({}^{\circ}\)C was about 710 MPa. This strength value is higher than the strengths of the Al-14 Si-2.5 Cu-0.5 Mg alloy (654 MPa) and Al\({}_{82}\)La\({}_{10}\)Fe\({}_{4}\)Ni\({}_{4}\) alloy (650 MPa) fabricated by SPS [51, 52]. Figure 7: XRD patterns of Al\({}_{82}\)Fe\({}_{14}\)Ni\({}_{4}\) amorphous alloys after heat treatment at (**a**,**d**) 480, (**b**,**e**) 600 and (**c**,**f**) 700 \({}^{\circ}\)C.  
Figure 3:0 Shrinkage curve recorded during the SPS processing of Al\({}_{\rm 8g}\)Fe\({}_{\rm 14}\)Ni\({}_{\rm 4}\) sample. Figure 3:1 SEM images of the fracture surfaces of Al\({}_{\rm 2g}\)Fe\({}_{\rm 14}\)Ni\({}_{\rm 4}\) samples sintered at (**a,b**) 450, (**c,d**) 500 and (**e,f**) 600 \({}^{\circ}\)C at different magnifications of 200\(\times\) and 3000\(\times\). The highest relative density of about 97.4% was obtained for the sample sintered at 600 \({}^{\circ}\)C. Porosity still existed in the sintered sample, which was the main reason behind the failure, as can be observed in Figure 3:2  
The XRD patterns of the sintered samples are presented in Figure 3:3 There is a peak shift to the higher diffraction angle of about 44\({}^{\circ}\) of the sintered samples. This indicates that aside from the amorphous phase, there is another nanocrystals' precipitation phase. For the sample sintered at 450 \({}^{\circ}\)C, diffraction peaks of fcc-Al can be detected (Figure 10b). The halo peak, which is characterized by the amorphous phase (Figure 10b) in the range of 43\({}^{\circ}\)-45\({}^{\circ}\), becomes narrow compared with a fully amorphous alloy (Figure 10a). This is consistent with the XRD of as-milled powders annealing at 450 \({}^{\circ}\)C, as is displayed in Figure 7d. At higher sintering temperatures of 500 and 600 \({}^{\circ}\)C, only the diffraction peaks of the nanocrystal \(\beta\)-bcc phase can be seen from the XRD patterns in Figure 10c,d. At these sintering temperatures, the crystallization and recovery of the crystal lattice occur, causing the characteristic peaks to sharpen and shift to the standard position.