Electron microscopy
 
Al-based Metallic-Glass Alloys
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Figure 3053a shows the critical cooling rate (Rc) and critical casting thickness (dc) for formation of various metallic glass alloys from melts as a function of reduced glass transition temperature (Trg).

Critical cooling rate and critical casting thickness for formation of various metallic glass alloys from melts as a function of reduced glass transition temperature
1: Ni
2: Fe89B11
3: Fe83B17
4: Fe41.5Ni41.5B17
5: Fe79Si10B11
6: Au55Pb22.5Sn22.5
7: Pt60Ni15P25
8: Mg65Cu25Y10
9: Zr65Cu17.5Ni10Al7.5
10: Zr52.5Ti5Cu17.9Ni14.6Al10
11: Ce68Al10Cu20Nb2

12: Ni62.4Nb37.6
13: Te
14: Fe91B9
15: Au77.8Ge13.8Si8.4
16: Co75Si15B10
17: Fe80P13C7
18: Pd82Si18
19: Pd77.5Cu6Si16.5
20: Zr57Nb5Cu15.4Ni12.6Al10
21: Au49Ag5.5Pd2.3Cu26.9Si16.3
22: Pt57.5Cu14.7Ni5.3P22.5
23: Pd40Ni40P20
24: Pd40Cu30Ni10P20
25: Ni75Si8B17
26: Ti34Zr11Cu47Ni8
27: Zr41.2Ti13.6Cu12.5Ni10Be22.5
28: La55Al25Ni10Cu10
29: Fe40Ni40P14B6
30: La55Al25Ni20
31: Zr60Al20Ni20

32: Ge2Sb2Te5

Figure 3053a. Critical cooling rate and critical casting thickness for formation of various metallic glass alloys from melts as a function of reduced glass transition temperature. The Al-based metallic-glass alloys are in green.

Figure 3053b shows the microstructure of an Al87Ni7Cu3Ce3 amorphous alloy. In the HAADF-STEM (Z-contrast) image, some brightest spots in white circles represent heavy Ce atoms or its small clusters (Z=58), while some darkest areas in red circles represent fcc-Al (Z=13) nanostructures in the amorphous matrix. However, the HRTEM image does not present clearly the structures of fcc-Al nanocrystals.

(a) HAADF-STEM image and (b) HRTEM image of an Al87Ni7Cu3Ce3 amorphous alloy
(a) HAADF-STEM image and (b) HRTEM image of an Al87Ni7Cu3Ce3 amorphous alloy
(a)
(a)

Figure 3053b. (a) HAADF-STEM image and (b) HRTEM image of an Al87Ni7Cu3Ce3 amorphous alloy. Adapted from [1]

 

 

 

 

 

[1] Eiji Abe, Atomic-Scale Characterization of Nanostructured Metallic Materials by HAADF/Z-contrast STEM, Materials Transactions, 44(10), 2035-2041, (2003).

 

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