Challenges in the Development of Aluminium-Based Bulk Amorphous Alloys

Kiminami, Cláudio Shyinti; Bassim, Nabil; Kaufman, Michael J.; Amateau, M.F.; Eden, Timothy J.; Galbraith, J. M.

doi:10.4028/www.scientific.net/kem.189-191.503

Cited by 27 publications

(12 citation statements)

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“…The microhardness values of Al 3 Ti, Al 5 CuTi 2 and nanocrystalline TiO 2 have been reported as 5.9, 3.4 and 4.7 GPa, respectively [35e37], all of which contribute to high hardness of the investigated composite. In related studies, hardness values in the range of about 5 GPa have been reported for high strength bulk amorphous Al 85 Ni 5 Y 8 Co 2 alloy [10] and bulk nanocrystalline Al 88 Mm 5 Ni 5 Fe 2 alloy [16]. Substituting the hardness (H v ) data in the well-known empirical relation for s y ¼ H v /3 [38], the predicted value of yield strength, s y of the sample sintered at 873 K appears to be 1867 MPa as shown in Table 1.…”

Section: Mechanical Propertiesmentioning

confidence: 95%

“…Dimitrov et al [16] have reported that it is not possible to compact nanocrystalline powders of Al 88 Mm 5 Ni 5 Fe 2 alloy at room temperature even with a pressure of 7.7 GPa. Kiminami et al [10] have recently reviewed the challenges in P/M processing of the high strength bulk amorphous alloys. During pressing at high pressure and temperature, there could be partial crystallization of the amorphous phase [7,16], or grain coarsening in the nanocrystalline product [17e19].…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and mechanical properties of mechanically alloyed and spark plasma sintered amorphous–nanocrystalline Al65Cu20Ti15 intermetallic matrix composite reinforced with TiO2 nanoparticles

et al. 2007

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Section: Mechanical Propertiesmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Microstructure and mechanical properties of mechanically alloyed and spark plasma sintered amorphous–nanocrystalline Al65Cu20Ti15 intermetallic matrix composite reinforced with TiO2 nanoparticles

et al. 2007

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“…During pressing at high pressure and temperature, there could be partial crystallization of the amorphous phase or grain coarsening of the nanocrystalline aggregate. [8,11] It is known that mechanical properties of nanocrystalline materials are highly sensitive to the presence of internal defects, heterogeneities, and grain size distributions [12][13][14] caused during the consolidation of the nanocrystalline powders. Hence, the consolidation process needs to be optimized for the production of dense nanocrystalline materials with reasonably narrow grain size distributions.…”

Section: Introductionmentioning

confidence: 99%

“…Hence, considerable success was achieved in the recent past in synthesizing Al-based engineering alloys in amorphous state or nanointermetallic phase dispersed amorphous matrix condition either by mechanical alloying or rapid solidification. [2][3][4][5][6][7][8][9][10] However, these novel materials are available only in the form of ribbon, wire, film, or powder, and are therefore difficult to consolidate into bulk components of large dimensions. Among different possibilities, hot/ warm pressing or extrusion is a possible method to fabricate the bulk sample from mechanically alloyed powders.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Evolution and Mechanical Properties of Nanointermetallic Phase Dispersed Al65Cu20Ti15 Amorphous Matrix Composite Synthesized by Mechanical Alloying and Hot Isostatic Pressing

Roy¹,

Mitra

Ojo

et al. 2011

Metall Mater Trans A

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The structure and mechanical properties of nanocrystalline intermetallic phase dispersed amorphous matrix composite prepared by hot isostatic pressing (HIP) of mechanically alloyed Al 65 Cu 20 Ti 15 amorphous powder in the temperature range 573 K to 873 K (300°C to 600°C) with 1.2 GPa pressure were studied. Phase identification by X-ray diffraction (XRD) and microstructural investigation by transmission electron microscopy confirmed that sintering in this temperature range led to partial crystallization of the amorphous powder. The microstructures of the consolidated composites were found to have nanocrystalline intermetallic precipitates of dispersed in amorphous matrix. An optimum combination of density (3.73 Mg/m 3 ), hardness (8.96 GPa), compressive strength (1650 MPa), shear strength (850 MPa), and Young's modulus (182 GPa) were obtained in the composite hot isostatically pressed (''hipped'') at 773 K (500°C). Furthermore, these results were compared with those from earlier studies based on conventional sintering (CCS), high pressure sintering (HPS), and pulse plasma sintering (PPS). HIP appears to be the most preferred process for achieving an optimum combination of density and mechanical properties in amorphous-nanocrystalline intermetallic composites at temperatures £773 K (500°C), while HPS is most suited for bulk amorphous alloys. Both density and volume fraction of intermetallic dispersoids were found to influence the mechanical properties of the composites.

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“…1,2) The formation of an amorphous single phase in Al-based alloys containing more than 50 at% Al was observed for the first time in 1981 in Al-Fe-B and Al-Co-B ternary alloys. 1) However, these amorphous alloys were extremely brittle and hence did not attract much attention.…”

Section: Introductionmentioning

confidence: 99%

Aluminum Alloy Based Nanocomposites Strengthened with Amorphous AlNiTiZr Phase

2011

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The concept to design a composite of the 7475 alloy strengthened with particles of an amorphous aluminum based alloy was studied in the present paper. Mechanical alloying (MA) process was applied to obtain amorphous structure of the powder of composition Al 70 Ni 10 Zr 10 Ti 10 (in at%). Elemental powders of this composition were ball milled for 60 h in a planetary high energy mill using steel balls. The estimated mean size of powder particles below 10 mm was much smaller than that of the initial elemental powders. The mean value of the microhardness of the milled powder was 384 HV and was significantly higher than that of initial powders. The dominant presence of the amorphous structure was confirmed using DSC studies, in which crystallization peaks were observed above 400 C. X-ray diffraction (XRD) patterns after various milling times confirmed a partial amorphization of the material. Additionally, weak maxima of Al 3 Zr 4 phase were identified. TEM studies of powders confirmed the formation of predominantly amorphous structure with some nanocrystalline inclusions of intermetallic phases identified as Al 3 Zr 4 , AlZr 3 , Al 3 Ni and Al 3 Ti. The amorphous powder was mixed (for a short time) with prealloyed 7475 alloy powder 40 h ball milled to obtain nanocrystalline grain size of powder's particles. Powders were hot pressed in vacuum, below the crystallization temperature at 380 C and pressure of 600 MPa in order to preserve amorphous and nanocrystalline grain structure. SEM studies of the composite containing 1/3 ball milled 7475 alloy and 2/3 of the amorphous powder allowed identifying low porosity and clean interface within the composite. The samples showed compression strength near 500 MPa and a few percent ductility. The cracks nucleated within the amorphous particles as resulted from SEM studies of the compressed samples.

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Challenges in the Development of Aluminium-Based Bulk Amorphous Alloys

Cited by 27 publications

References 0 publications

Microstructure and mechanical properties of mechanically alloyed and spark plasma sintered amorphous–nanocrystalline Al65Cu20Ti15 intermetallic matrix composite reinforced with TiO2 nanoparticles

Microstructure and mechanical properties of mechanically alloyed and spark plasma sintered amorphous–nanocrystalline Al65Cu20Ti15 intermetallic matrix composite reinforced with TiO2 nanoparticles

Microstructural Evolution and Mechanical Properties of Nanointermetallic Phase Dispersed Al65Cu20Ti15 Amorphous Matrix Composite Synthesized by Mechanical Alloying and Hot Isostatic Pressing

Aluminum Alloy Based Nanocomposites Strengthened with Amorphous AlNiTiZr Phase

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