Effect of Si addition on glass forming ability and thermal stability of Al–Fe–La alloys

The quantitative relationship between microstructure and mechanical property of a melt spun Al–Mg alloy

“…Consequently, a vast number of research efforts have been attempted to improve the thermal stability, concentrating on the optimization of the compositions [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. In an effort to stabilize the amorphous alloys, a series of strategies have been developed, aiming at minimizing the diffusion ability of the component atoms, which is considered as a prerequisite condition for the occurrence of crystallization: (i) enhancing the differences between atomic sizes by introducing atoms with much larger and/or much smaller sizes in order to improve the packing density of the component atoms, e.g., adding Y to Fe 63 Zr 8 Co 6 Al 1 -Mo 7 B 15 [5], Sc to Zr 52.5 Cu 17.9 Ni 14.6 Al 10 Ti 5 [6], O to Zr 80 Pt 20 [7], Si to Cu 47 Ti 34 Zr 11 Ni 8 [8], and B, Si and Pb to Zr 52.5 Cu 17.9 Ni 14.6 Al 10 Ti 5 [9], (ii) increasing the magnitude of negative heats of mixing between component elements in order to promote chemical short-range ordering and thus to limit long-range diffusion of atoms, e.g., adding Pd to Al-Y-Ni-based amorphous alloys [10], increasing B concentrations in Fe-Zr-B-Nb amorphous alloys [11], and adding Si to Al-Fe-La amorphous alloys [12], (iii) introducing component elements with very large atomic sizes and thus extremely low diffusion ability, e.g., selecting Hf as a component element in the Co-Hf-B system [13], and (iv) increasing the number of components as much as possible, namely, 'confusion principle' as suggested by Greer [14]. In order to achieve high thermal stability in the RS crystalline alloys, the elements that exhibit very low diffusivity in the matrix are usually selected as alloying elements.…”

“…Due to the lightweight attribute, melt spun Al alloys (both amorphous and crystalline) have been paid particular attention and extensive experimental studies have been conducted on this class of melt spun materials [10,12,16,[23][24][25][26][27][28][29][30][31][32], which involve characterization of microstructures and testing of mechanical properties. The available experimental results reveal brittleness of amorphous ribbons [30][31][32], which limits their widespread applications.…”

Fabrication of Al-based bulk metallic glass by mechanical alloying and vacuum hot consolidation

“…amorphous composites compared with direct cooling from the melting metal liquid [11][12][13][14][15]. This is especially important for the alloy systems with low GFA in preparing amorphous powders and subsequently consolidating the amorphous powders into bulk samples with unlimited thickness and shape, using the viscous flow behavior in the supercooled liquid region [16][17][18][19].…”

Thermal stability of the Al70Ni10Ti10Zr5Ta5 amorphous alloy powder fabricated by mechanical alloying

“…It has been reported that many types of amorphous alloy powders can be consolidated into bulk forms via hot pressing [11], spark plasma sintering [12], extrusion [13], high pressure torsion [14] and equal channel angular extrusion [15]. However, since all these consolidation processes are performed at temperatures within the supercooled liquid region, a higher crystallization temperature and a wider supercooled liquid region or higher thermal stability are essential for the consolidation operation [16][17][18][19][20]. Accordingly, studies have been carried out recently to find suitable Al-based amorphous alloy powders for processing corresponding bulk amorphous alloys in our group.…”