Amorphous phase formation during spray forming of Al84Y3Ni8Co4Zr1 alloy

Afonso, Conrado Ramos Moreira; Bolfarini, Claudemiro; Kiminami, Cláudio Shyinti; Bassim, Nabil; Kaufman, Michael J.; Amateau, M.F.; Eden, Timothy J.; Galbraith, J. M.

doi:10.1016/s0022-3093(01)00392-1

Cited by 29 publications

(29 citation statements)

References 5 publications

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“…Spray forming process [11][12][13][14] has been increasingly used to produce these composites in bulk dimension. [13][14][15][16] In this study, an as-spray-formed Al 89 La 6 Ni 5 nanophase composite 13) mixed together with 30% primary crystals (1 mm in diameter) was produced. In addition to the nanoscale fcc-Al crystals effect mentioned above, the primary crystals are another origin associated with the enhanced strength of the composite.…”

Section: Introductionmentioning

confidence: 99%

Thermal Stability and Mechanical Properties of Spray-Formed and Melt-Spun Al89La6Ni5 Metallic Glass Matrix Composites

et al. 2007

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A spray-formed Al 89 La 6 Ni 5 metallic glass matrix composite plate was obtained in thickness of 1 mm and diameter of 200 mm, comprising over 64% primary crystals (e.g. Al 11 La 3 ) uniformly dispersed in the glass matrix. The microstructure can not be achieved by annealing corresponding amorphous precursor. The crystals existing in the glass matrix were found to increase the hardness of the composite. Through nanoindentation test, the hardness and modulus of the composite at ambient temperature were found superior than its amorphous ribbon counterpart. The hardness of the composite was estimated with the rule of mixture from the constituents to be 4.4 GPa, which agreed well with the nanoindentation results. From loss modulus measurement and TMA test at elevated temperatures, a weak T g signal in the range of 213-240 C was revealed in the as-spray-formed composite. Furthermore, the dimension shrinkage of the composite was only 0.5% during the TMA test, which is much smaller than that of amorphous ribbon counterpart by up to 20%. The enhanced hardness by constituent second phases and the dimension stability of the composite are associated with their inherent microstructure, the primary crystals in particular.

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Section: Introductionmentioning

confidence: 99%

Thermal Stability and Mechanical Properties of Spray-Formed and Melt-Spun Al89La6Ni5 Metallic Glass Matrix Composites

et al. 2007

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“…Figure 5 shows microstructures of samples extracted from the center region of the deposit obtained by optical microscopy (OM). In Figure 5a it can be observed the high volume fraction of irregular porosity (%P ≅ 8%) near the substrate surface (3 mm thick) indicating a deposition process with high volume fraction of solid particles 19,20 . Figure 5b shows the microstructure associated with the 10 mm thick region of the deposit.…”

Section: Resultsmentioning

confidence: 99%

“…The inset in the DSC graphic shows a SEM image of an amorphous (featureless) powder around 15 µm 19,20 . The presence of an amorphous phase is a reasonable hypotheses considering the cooling rates prevailing during solidification of very fine powders, 10 5 -10 6 K/s.…”

Section: Resultsmentioning

confidence: 99%

Rapid solidification of an Al-5Ni alloy processed by spray forming

et al. 2012

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Recently, intermetallic compounds have attracted much attention due to their potential technological applications as high-temperature materials. In particular the intermetallic compounds, associated with the Al-Ni binary system stand out as promising candidates for high-temperature materials for the use in harsh environments. It is expected that a bulk Al-Ni alloy may exceed the strength of many commercial materials. The great challenge in developing these alloys is to manipulate the solidification thermal parameters in order to obtain the desired microstructural features. One of the indicated routes to obtain very refined intermetallic phases dispersed in the microstructure is the spray forming process. The dendritic and eutectic growth dependences on cooling rate are already known for directionally solidified (DS) hypoeutectic Al-Ni alloys. In the case of rapidly solidified (RS) samples, extrapolations of such experimental laws are needed, which can be very helpful to estimate realistic values of high cooling rates imposed during the spray forming process. The present study aims to compare directionally solidified and spray-formed Al-5 wt. (%)Ni alloy samples with a view to providing a basis for understanding how to control solidification parameters and the as-cast microstructure. The Al-5.0 wt. (%)Ni alloy was shown to have a cellular morphology for the overspray powder size range examined (up to 500 µm). The mean cell spacing decreased from 5.0 to 1.1 µm with the decrease in the powder average diameter. It was found that the experimental cooling rates imposed during the atomization step of the overspray powder solidification varied from 10 3 to 2.10 4 K/s. The DSC trace depicted a crystallization peak of an amorphous structure fraction in the smallest Al-5.0 wt. (%)Ni alloy powder size range (<32 µm) estimating a 15 µm critical diameter of amorphous powder in the binary Al 97.5 Ni 2.5 (at%) alloy.

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“…DSC traces of amorphous metals and metallic glasses. Left: Alloy Al84Ni8Co4Y3Zr1 presents an "amorphous metal" behavior, i. e., no Tg and primary nanocrystallization; Right: Alloy Al84Ni5Co2Y9 presents a "metallic glass" behavior, i. e., upon heating, the alloy shows Tg before Tx (onset of the crystallization process) [8]. Figure 7.…”

Section: Amorphous Metals and Metallic Glassesmentioning

confidence: 99%

“…The deposits and powder were analyzed by X-ray diffraction using Cu K a radiation (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) equipped with an energy dispersive spectrometry (EDS) system, electron probe microanalysis (EPMA) and transmission electron microscopy (TEM), also equipped with an EDS system. Details of the processing and characterization of overspray powders and deposit have been presented elsewhere [14,15]. Figure 8 shows the overspray powder of the Al 85 Y 8 Ni 5 Co 2 alloy processed at G/M =10.…”

Section: Amorphous Metals and Metallic Glassesmentioning

confidence: 99%

Processing of glass former alloys by spray forming

Kiminami

Filho

Bolfarini³

2010

Materialwissenschaft Werkst

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Spray forming (SF) can be classified as a two-stage manufacturing process in which solidification begins during particle flight, a relatively rapid solidification step that ends as the deposit builds up, with the remaining liquid droplets solidifying at considerably slower rates. Due to the high cooling rate of the atomization step and the special conditions of deposit buildup, with incoming materials dynamically refining the solidifying material, as-sprayed deposits typically display a fine-scale microstructure which may also exhibit some extended solid solubility and metastable phases. Our group has studied several alloys in order to investigate the potential formation of novel microstructures by this process. This paper describes some of the results obtained by spray forming of aluminum-and iron-based alloys, whose compositions derive from rapid solidification studies aimed at obtaining amorphous structures. 96 Nb 4 alloy, which displayed the highest glass-forming ability among the Fe-based alloys, showed a high volume percent of amorphous phase formation up to 4mm thickness of the deposit, a similar value obtained for this alloy when processed by copper mold casting.

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Amorphous phase formation during spray forming of Al84Y3Ni8Co4Zr1 alloy

Cited by 29 publications

References 5 publications

Thermal Stability and Mechanical Properties of Spray-Formed and Melt-Spun Al<SUB>89</SUB>La<SUB>6</SUB>Ni<SUB>5</SUB> Metallic Glass Matrix Composites

Thermal Stability and Mechanical Properties of Spray-Formed and Melt-Spun Al<SUB>89</SUB>La<SUB>6</SUB>Ni<SUB>5</SUB> Metallic Glass Matrix Composites

Rapid solidification of an Al-5Ni alloy processed by spray forming

Processing of glass former alloys by spray forming

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