Non-equilibrium solidification of undercooled metallic metls

Herlach, D.M.

doi:10.1016/0927-796x(94)90011-6

Cited by 529 publications

(176 citation statements)

References 165 publications

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“…Rapid solidification at high cooling rates is an effective route to the formation metallic glass, especially for deep eutectic melts [14] as this reduces the normalised glass transition temperature. Recently, Lu et al [29] obtained small amounts of an amorphous phase in bulk eutectic Ni 70.2 Si 29.8 alloy under slow cooling conditions (about 1 K s -1 ).…”

Section: Discussionmentioning

confidence: 99%

“…Another potential route to improve this lack of formability is non-equilibrium processing via rapid solidification, with the resulting refined grain structure [14][15][16] and the presence of antiphase domains and disorder-order structures improving ductility [17,18]. Moreover, in this route annealing subsequent to forming can restore the desirable mechanical properties of the intermetallic.…”

Section: Introductionmentioning

confidence: 99%

“…This technique is an effective method to form and retain nonequilibrium phases, e.g. supersaturated solid solution, metastable phase and metallic glass [14], due to the high undercoolings likely through melt sub-division and the high postrecalescence cooling rates achieved. This extends our previous work on this alloy by both melt undercooling [27], wherein a eutectic structure between and was observed and drop tube processing, wherein a previously unobserved 1 -Ni 25 Si 9 eutectic was detected [30,31].…”

Section: Introductionmentioning

confidence: 99%

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Microstructural Evolution and Phase Formation in Rapidly Solidified Ni-25.3 At. Pct Si Alloy

Cao

Mullis

2015

Metall Mater Trans A

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The drop-tube technique was used to solidify droplets of the Ni-25.3 at.% Si alloy at high cooling rates. XRD, SEM and TEM analysis revealed that the metastable phase, Ni 25 Si 9 , formed as the dominant phase in all ranges of the droplets, with -Ni 31 Si 12 and 1 -Ni 3 Si also being present. Three different microstructures were observed: the regular and anomalous eutectic structures and near single phase structure containing small inclusions of a second phase, termed here a heteroclite structure. Both eutectic structures comprise alternating lamellae of Ni 25 Si 9 and 1 -Ni 3 Si, which, we conjecture, is a consequence of an unobserved eutectic reaction between the Ni 25 Si 9 and 1 -Ni 3 Si phases. The matrix of the heteroclite structure is also identified as the metastable phase Ni 25 Si 9 , in which twined growth is observed in the TEM. As the cooling rate is increased (particle size decreased) the proportion of droplets displaying the entire heteroclite structure tends to increase, with its fraction increasing from 13.91% (300-500 µm) to 40.10% (75-106 µm). The thermodynamic properties of the Ni 25 Si 9 phase were also studied by in-situ heating during XRD analysis and by DTA. This showed the decomposition of Ni 25 Si 9 to 1 and -Ni 31 Si 12 for temperatures in excess of 790 K (517°C).

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Microstructural Evolution and Phase Formation in Rapidly Solidified Ni-25.3 At. Pct Si Alloy

Cao

Mullis

2015

Metall Mater Trans A

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“…2 However, until now, in dendrite growth V D has been used as a free parameter to fit the dendrite velocity-undercooling data. 14 The objective of the present work is to measure independently V D and the dendrite velocity-undercooling function in the same alloy system, thereby eliminating this key free parameter and providing a rigorous test of theory. Additionally, we measure independently the bulk liquid diffusivity D L thereby fixing the remaining free parameter used in the theory.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, dilute Ni-base alloys such as Ni 99 Zr 1 show an excellent undercooling behavior in experiments of containerless processing in an electromagnetic levitation coil due to its high melting temperature. 14 …”

Section: Introductionmentioning

confidence: 99%

Parameter-free test of alloy dendrite-growth theory

Arnold

Aziz²,

Schwarz³

et al. 1999

Phys. Rev. B

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In rapid alloy solidification the dendrite-growth velocity depends sensitively on the deviations from local interfacial equilibrium manifested by kinetic effects such as solute trapping. The dendrite tip velocityundercooling function was measured in dilute Ni͑Zr͒ over the range 1-25 m/s and 50-255 K using electromagnetic levitation techniques and compared to theoretical predictions of the model of Trivedi and colleagues for dendritic growth with deviations from local interfacial equilibrium. The input parameter to which the model predictions are most sensitive, the diffusive speed V D characterizing solute trapping, was not used as a free parameter but was measured independently by pulsed laser melting techniques, as was another input parameter, the liquid diffusivity D L . Best-fit values from the pulsed laser melting experiment are V D ϭ26 m/s and D L ϭ2.7ϫ10 Ϫ9 m 2 /s. Inserting these values into the dendrite growth model results in excellent agreement with experiment with no adjustable parameters. ͓S0163-1829͑99͒02101-3͔

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Phase Evolution in Solidification Process of Germanium at High Pressure

Zhang

et al. 1998

Cryst. Res. Technol.

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Non-equilibrium solidification of undercooled metallic metls

Cited by 529 publications

References 165 publications

Microstructural Evolution and Phase Formation in Rapidly Solidified Ni-25.3 At. Pct Si Alloy

Microstructural Evolution and Phase Formation in Rapidly Solidified Ni-25.3 At. Pct Si Alloy

Parameter-free test of alloy dendrite-growth theory

Phase Evolution in Solidification Process of Germanium at High Pressure

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