Prediction of phase selection in rapid solidification using time dependent nucleation theory

Understanding the rapid solidification behavior characteristics, nucleation undercooling, and nucleation mechanism is important for modifying the microstructures and properties of metal alloys. In order to investigate the rapid solidification behavior in-situ, accurate measurements of nucleation undercooling and cooling rate are required in most rapid solidification processes, e.g., in additive manufacturing (AM). In this study, differential fast scanning calorimetry (DFSC) was applied to investigate the nucleation kinetics in a single micro-sized Al-20Si (mass%) particle under a controlled cooling rate of 5000 K/s. The nucleation rates of primary Si and secondary α-Al phases were calculated by a statistical analysis of 300 identical melting/solidification experiments. Applying a model based on the classical nucleation theory (CNT) together with available thermodynamic data, two different heterogeneous nucleation mechanisms of primary Si and secondary α-Al were proposed, i.e., surface heterogeneous nucleation for primary Si and interface heterogenous nucleation for secondary α-Al. The present study introduces a practical method for a detailed investigation of rapid solidification behavior of metal particles to distinguish surface and interface nucleation.

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Phase Selection in Sub-Rapidly Solidified Au-20Sn Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.817.325 ◽

2015 ◽

Vol 817 ◽

pp. 325-330

Author(s):

Yu Hai Qu ◽

Kai Jin Yang ◽

Yan Tian Zhou ◽

Yong Mao ◽

Wei Zhang ◽

...

Keyword(s):

Cooling Rate ◽

Nucleation Theory ◽

Classical Nucleation Theory ◽

Copper Mold ◽

Cooling Rates ◽

Phase Selection ◽

Graphite Mold ◽

Injection Casting ◽

Rapidly Solidified ◽

Ausn Phase

The sub-rapidly solidified Au-20Sn eutectic alloys were prepared by four different solidification pathways, such as, graphite mold conventional casting, graphite mold injection casting, copper mold injection casting, and water-cooled copper mold suction casting. The precipitating sequences of competing primary phases of sub-rapidly solidified Au-20Sn alloys with four different cooling rates were investigated. The results show that phase selection process is related to the cooling rates during sub-rapid solidification process. The primary ζ'-Au5Sn phase with developed dendrites precipitate at low cooling rate (2.4×10−4.2×102K/min) and the morphologies of the primary ζ'-Au5Sn change to rosette-like at higher cooling rate (9.0×103K/min). While the cooling rate reaches to 3.5×104K/min, the primary ζ'-Au5Sn phase can be suppressed but δ-AuSn phase will precipitate prior to the ζ'-Au5Sn phase. On the basis of the classical nucleation theory and transient nucleation theory, the process of competitive nucleation between the ζ'-Au5Sn phase and the δ-AuSn phase were analyzed for sub-rapid solidified Au-20Sn alloy. The theoretical calculations are consistent with the experimental investigations.

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Application of classical nucleation theory to phase selection and composition of nucleated nanocrystals during crystallization of Co-rich (Co,Fe)-based amorphous precursors

Acta Materialia ◽

10.1016/j.actamat.2010.05.015 ◽

2010 ◽

Vol 58 (14) ◽

pp. 4804-4813 ◽

Cited By ~ 13

Author(s):

P.R. Ohodnicki Jr. ◽

D.E. Laughlin ◽

M.E. McHenry ◽

M. Widom

Keyword(s):

Nucleation Theory ◽

Classical Nucleation Theory ◽

Phase Selection

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Nucleation-Controlled Phase Selection in Rapid Solidification from Undercooled Melt of DyMnO3

Journal of the Japan Institute of Metals and Materials ◽

10.2320/jinstmet.j2020061 ◽

2021 ◽

Vol 85 (4) ◽

pp. 155-161

Author(s):

You Hayasaka ◽

Kazuhiko Kuribayashi ◽

Suguru Shiratori ◽

Shumpei Ozawa

Keyword(s):

Rapid Solidification ◽

Phase Selection ◽

Undercooled Melt

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Microstructure and Phase Selection of Undercooled Single-Phase Fe-Co Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.154-155.1624 ◽

2010 ◽

Vol 154-155 ◽

pp. 1624-1628

Author(s):

Ning Liu ◽

Gen Cang Yang ◽

Feng Liu

Keyword(s):

Theoretical Calculation ◽

Single Phase ◽

Critical Value ◽

Nucleation Theory ◽

Experimental Result ◽

Classical Nucleation Theory ◽

Phase Selection ◽

Maximum Undercooling ◽

Bcc Phase ◽

Selection Of

Fe-Co single-phase alloy melts with different Co contents were undercooled using fluxing method. The maximum undercooling DT = 457K (relative undercooling DT/Tm=0.259) was achieved in this work. At low undercooling (DT), single-phased microstructure was observed, but metastable bcc phase emerged in the as-solidified microstructure once DT exceeded a critical value, DTcrit. In the presence of classical nucleation theory, phase selection in the undercooled Fe-Co melt was investigated, and the theoretical calculation was coincided with the experimental result.

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Time dependent interface stability during rapid solidification

Journal of Applied Physics ◽

10.1063/1.371278 ◽

1999 ◽

Vol 86 (7) ◽

pp. 3682-3687 ◽

Cited By ~ 2

Author(s):

K. Greven ◽

A. Ludwig ◽

P. R. Sahm

Keyword(s):

Rapid Solidification ◽

Time Dependent ◽

Interface Stability

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Nucleation Behavior and Solid-Liquid Interfacial Energy of Polytetrahedral Phases

MRS Proceedings ◽

10.1557/proc-580-245 ◽

1999 ◽

Vol 580 ◽

Cited By ~ 2

Author(s):

Dirk Holland-Moritz

Keyword(s):

Interfacial Energy ◽

Orthorhombic Phase ◽

Nucleation Theory ◽

Classical Nucleation Theory ◽

Phase Selection ◽

Nucleation Behavior ◽

Σ Phase ◽

Selection Behavior ◽

Liquid Interfacial Energy ◽

Solid Liquid

AbstractAccording to classical nucleation theory the nucleation- and phase-selection behavior of undercooled meltallic melts is strongly dependent on the solid-liquid interfacial energy.A structural approach to the modelling of the interfacial energy for simple melt-crystal interfaces (fcc, hcp, bcc) was developed a number of years ago [1-4]. This approach is extended to polytetrahedral phases using numerical simulation. Results of these calculations are presented for different polytetrahedral structures: the tetragonal σ-phase in Ni-V, the monoclinic phase λ-Al13Fe4, the orthorhombic phase μ-Al5Fe2 and the icosahedral quasicrystalline I-phase in Al-Pd-Mn. The numerically estimated values for the solid-liquid interfacial energy are compared with results from experiments on the undercooling- and phase-selection behavior.

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Multiscale analysis of the effect of competitive nucleation on phase selection in rapid solidification of rare-earth ternary magnetic materials

Acta Materialia ◽

10.1016/j.actamat.2011.09.009 ◽

2012 ◽

Vol 60 (1) ◽

pp. 112-122 ◽

Cited By ~ 9

Author(s):

M. Krivilyov ◽

T. Volkmann ◽

J. Gao ◽

J. Fransaer

Keyword(s):

Rare Earth ◽

Magnetic Materials ◽

Rapid Solidification ◽

Multiscale Analysis ◽

Phase Selection

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Microstructural Analysis of Rapid Solidification and Undercooling in the Al-Ge System

MRS Proceedings ◽

10.1557/proc-28-335 ◽

1983 ◽

Vol 28 ◽

Author(s):

M.J. Kaufman ◽

H.L. Fraser

Keyword(s):

Electron Beam ◽

Rapid Solidification ◽

Local Heating ◽

Microstructural Analysis ◽

Liquid Droplets ◽

Amorphous Films ◽

Phase Selection ◽

Heating Source ◽

Electron Microscopes ◽

Microscope Heating Stage

ABSTRACTSubmicron powders, amorphous films and melt spun ribbons of various Al-Ge alloys have been analyzed to determine the relative roles of undercooling and cooling rate in the production of non-equilibrium structures. All analyses were performed in transmission electron microscopes equipped with energy dispersive x-ray spectrometers. The submicron powders, produced by electro-hydrodynamic atomization, were analyzed in their as-received condition and then annealed and/or melted using the electron beam as a local heating source. Once molten, the liquid droplets were undercooled at different cooling rates by varying the rate of beam obstruction. In this manner, a number of different microstructures were produced. These included metastable crystalline phases and mixed amorphous/crystalline structures. By combining this technique with a microscope heating stage, it was possible to carry out controlled dynamic undercooling experiments and determine phase selection as a function of undercooling and composition. The amorphous films were rapidly heated with the electron beam in the microscope and metastable as well as stable phases were produced. The results of these complementary analyses will be compared and discussed with reference to current models and theories of rapid solidification.

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