Microstructural evolution in spray-formed and melt-spun Al85Nd5Ni10 bulk hybrid composites

Guo, Mingsheng; Tsao, Chi-Yuan A.; Huang, J.C.; Jang, J.S.C.

doi:10.1016/j.intermet.2006.01.041

Cited by 18 publications

(17 citation statements)

References 18 publications

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“…The hardness of the primary crystals is taken as 5.1 GPa. 14) A LaSD composite consists of 36 v/o amorphous phase and up to 64 v/o crystals. As a result, the hardness of the overall glass matrix composite LaSD can be estimated to be 4.4 GPa (0:36 Â 3:1 þ 0:64 Â 5:1).…”

Section: Nanoindentation and Microhardnessmentioning

confidence: 99%

“…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%

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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: Nanoindentation and Microhardnessmentioning

confidence: 99%

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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“…Compared to the second exothermic peak, the following third exothermic peak is large. This might be due to the dissolution of Ni clusters that are formed at quenching as reported in an Al-5Nd-10Ni alloy [34]. The second exothermic peak (small peak) is more clearly observed in the specimens with a lower neodymium concentration.…”

Section: X-ray Diffraction and Dsc Studiesmentioning

confidence: 53%

Microhardness and morphologic characteristics of rapidly solidified Al-12Si-8Ni-5Nd alloy

Karaköse

Keskín

2010

Met. Mater. Int.

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Al-Si-Ni-Nd alloys with a nominal composition of Al-12 wt.% Si-8 wt.% Ni-5 wt.% Nd alloy are prepared by a conventional casting (ingot) and melt spinning technique at different cooling rates (v). The effects of the rapid solidification rate on the microstructures and microhardness performances of the specimen alloys are investigated in detail. The results obtained by the XRD, SEM and DSC show that the ingot and melt spun alloys have a multiphase structure. When v is 5 m/s, the alloy consists of four phases namely α-Al, intermetallic Al 3 Ni, Al 11 Nd 3 , and fcc Si. The melt-spun ribbons are completely composed of α-Al and eutectic Si phases, and primary silicon is not observed when v increases to 20 m/s, 25 m/s, 30 m/s and 35 m/s. The XRD analysis indicated that the solubility of Si in the α-Al matrix increases greatly with the rapid solidification. The change in microhardness is discussed based on the microstructural observations. The microhardness values of the melt spun ribbons are about three times higher than those of ingot counterparts.

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“…RESULTS AND DISCUSSION A. Spray-Formed Material Figure 1 shows the billet base contained macropore defects due to initial process instability, while the rest of the billet was free of macrodefects, containing 2 to 3 area pct porosity typical of spray-formed material and generally lower than previously spray-formed amorphous and nanostructured alloy compositions from the literature. [1][2][3][4][5] However, when compared with the usual high microstructural homogeneity of spray-formed conventional Al alloys, [16] the microstructure was inhomogeneous, as shown in the unetched microstructure in There was a high intermetallic second-phase particle fraction, approaching 50 pct in some regions, within an overall complex and fine-scale microstructure. The microstructure comprised three regions: (I) near spherical presolidified droplets containing submicron particles; (II) micron-sized particles within swirls originating from relatively large liquid droplets (ca.…”

Section: Methodsmentioning

confidence: 99%

“…Using a relatively high gas to metal mass flow ratio to enhance the cooling rate, billets contained up tõ 76 vol pct of an amorphous Al-rich phase but suffered from high porosity because of insufficient liquid feeding on the billet top surface. Al-RE-TM (RE = rare earth, TM = transition metal) alloys were spray formed by Guo et al [3][4][5] A spray-formed 1-kg, 230-mm-diameter, and 3-mm-thick plate of Al 89 La 6 Ni 5 had~36 vol pct of an Al-rich phase; while a 2-kg, 230-mm-diameter, and 30-mm-thick plate of Al 85 Nd 5 Ni 10 alloy contained 63 vol pct amorphous Al-rich phase. While it has been shown that spray forming of complex composition alloys that form glasses or nanostructured materials in powders or ribbons is feasible, so far this has only been possible where low porosity and homogeneity were sacrificed and, by modern spray forming standards, very small deposits were manufactured.…”

Section: Introductionmentioning

confidence: 99%

Spray Forming of Bulk Ultrafine-Grained Al-Fe-Cr-Ti

Banjongprasert

Hogg

Liotti

et al. 2010

Metall Mater Trans A

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An Al-2.7Fe-1.9Cr-1.8Ti alloy has been spray formed in bulk and the microstructure and properties compared with those of similar alloys produced by casting, powder aomization (PA), and mechanical alloying (MA) routes. In PA and MA routes, a nanoscale metastable icosahedral phase is usually formed and is known to confer high tensile strength. Unlike previous studies of the spray forming of similar Al-based metastable phase containing alloys that were restricted to small billets with high porosity, standard spray forming conditions were used here to produce a~98 pct dense 19-kg billet that was hot isostatically pressed (''HIPed''), forged, and/or extruded. The microstructure has been investigated at all stages of processing using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and synchrotron X-ray diffraction (XRD) at the Diamond Light Source. Consistent with the relatively low cooling rate in spray forming under standard conditions, the microstructure showed no compelling evidence for the formation of metastable icosahedral phases. Nonetheless, after downstream processing, the spray-formed mechanical properties as a function of temperature were very similar to both PA rapid solidification (RS) materials and those made by MA. These aspects have been rationalized in terms of the typical phases, defects, and residual strains produced in each process route.

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Microstructural evolution in spray-formed and melt-spun Al85Nd5Ni10 bulk hybrid composites

Cited by 18 publications

References 18 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

Microhardness and morphologic characteristics of rapidly solidified Al-12Si-8Ni-5Nd alloy

Spray Forming of Bulk Ultrafine-Grained Al-Fe-Cr-Ti

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