Solidification of Undercooled Monotectic Alloys

1981 ◽  
Vol 9 ◽  
Author(s):  
J. H. Perepezko ◽  
C. Galaup ◽  
K. P. Cooper
Keyword(s):  
Phase Separation ◽  
Critical Point ◽  
Phase Distribution ◽  
Segregation Pattern ◽  
Miscibility Gap ◽  
Coarse Scale ◽  
Wetting Behavior ◽  
Liquid Segregation ◽  
Compositional Segregation

ABSTRACTDuring the processing of monotectic alloys large compositional segregation of the liquid can precede final solidification. Under normal treatment a coarse scale phase distribution is obtained as a result of convection and sedimentation effects which may be minimized by microgravity processing. In undercooled droplets (5–20μ) of Bi-Ga alloys with compositions near the monotectic point, a finescale segregation has been observed and is similar to that formed during a microgravity treatment of bulk samples. Near the critical point of the miscibility gap, Bi-rich alloys exhibit an undercooling prior to phase separation, while in Ga-rich alloys the onset of phase separation is at the miscibility gap boundary. Similarly, in Cu-Pb alloys an undercooling below the miscibility gap prior to phase separation is observed for Cu-rich alloys, but not for Pb-rich alloys near the critical point. These observations are consistent with the operation of a critical point wetting behavior which can modify the liquid segregation pattern during microgravity treatment.

Phase separation of binary mixtures induced by soft centrifugal fields

2021 ◽  
Author(s):  
Thomas Zemb ◽  
Rose Rosenberg ◽  
Stjepan Marčelja ◽  
Dirk Haffke ◽  
Jean-François Dufrêche ◽  
...  
Keyword(s):  
Phase Separation ◽  
Critical Point ◽  
Binary Mixtures ◽  
Liquid Mixture ◽  
Model System ◽  
Binary Liquid Mixture ◽  
Miscibility Gap ◽  
Critical Fluctuations ◽  
Binary Liquid

We use the model system ethanol–dodecane to demonstrate that giant critical fluctuations induced by easily accessible weak centrifugal fields as low as 2000g can be observed above the miscibility gap even far from the critical point of a binary liquid mixture.

scholarly journals Universality class of the motility-induced critical point in large scale off-lattice simulations of active particles.

Soft Matter ◽  
2021 ◽  
Author(s):  
Claudio Maggi ◽  
Matteo Paoluzzi ◽  
Andrea Crisanti ◽  
Emanuela Zaccarelli ◽  
Nicoletta Gnan
Keyword(s):  
Phase Separation ◽  
Critical Point ◽  
Computer Simulations ◽  
Large Scale ◽  
Universality Class ◽  
Critical Behaviour ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Active Particles ◽  
Two Dimensional Model

We perform large-scale computer simulations of an off-lattice two-dimensional model of active particles undergoing a motility-induced phase separation (MIPS) to investigate the systems critical behaviour close to the critical point...

Microstructure development in furfuryl resin-derived microporous glassy carbons

1996 ◽  
Vol 11 (9) ◽  
pp. 2338-2345 ◽  
Author(s):  
Kristen Persels Constant ◽  
Jonq-Ren Lee ◽  
Yet-Ming Chiang
Keyword(s):  
Phase Separation ◽  
Ethylene Glycol ◽  
Glassy Carbon ◽  
Thermal History ◽  
Liquid State ◽  
Furfuryl Alcohol ◽  
Time Dependent ◽  
Miscibility Gap ◽  
Microstructure Development

The processing of microporous glassy carbon derived from furfuryl alcohol and ethylene glycol mixtures has been studied, with emphasis on understanding and controlling microstructure development. It is shown that this system exhibits a polymerization-dependent miscibility gap, and that the carbon microstructure is determined by phase separation in the liquid state. Variations in carbon microstructure with composition and thermal history can be understood in terms of the time-dependent immiscibility and resulting phase separation.

scholarly journals Computation of liquid-liquid equilibria and phase stabilities: implications for RH-dependent gas/particle partitioning of organic-inorganic aerosols

2010 ◽  
Vol 10 (16) ◽  
pp. 7795-7820 ◽  
Author(s):  
A. Zuend ◽  
C. Marcolli ◽  
T. Peter ◽  
J. H. Seinfeld
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Water Solubility ◽  
Inorganic Compounds ◽  
Liquid Phase Separation ◽  
Miscibility Gap ◽  
Inorganic Aerosols ◽  
Particulate Mass ◽  
Inorganic Aerosol ◽  
Liquid Liquid Phase Separation

Abstract. Semivolatile organic and inorganic aerosol species partition between the gas and aerosol particle phases to maintain thermodynamic equilibrium. Liquid-liquid phase separation into an organic-rich and an aqueous electrolyte phase can occur in the aerosol as a result of the salting-out effect. Such liquid-liquid equilibria (LLE) affect the gas/particle partitioning of the different semivolatile compounds and might significantly alter both particle mass and composition as compared to a one-phase particle. We present a new liquid-liquid equilibrium and gas/particle partitioning model, using as a basis the group-contribution model AIOMFAC (Zuend et al., 2008). This model allows the reliable computation of the liquid-liquid coexistence curve (binodal), corresponding tie-lines, the limit of stability/metastability (spinodal), and further thermodynamic properties of multicomponent systems. Calculations for ternary and multicomponent alcohol/polyol-water-salt mixtures suggest that LLE are a prevalent feature of organic-inorganic aerosol systems. A six-component polyol-water-ammonium sulphate system is used to simulate effects of relative humidity (RH) and the presence of liquid-liquid phase separation on the gas/particle partitioning. RH, salt concentration, and hydrophilicity (water-solubility) are identified as key features in defining the region of a miscibility gap and govern the extent to which compound partitioning is affected by changes in RH. The model predicts that liquid-liquid phase separation can lead to either an increase or decrease in total particulate mass, depending on the overall composition of a system and the particle water content, which is related to the hydrophilicity of the different organic and inorganic compounds. Neglecting non-ideality and liquid-liquid phase separations by assuming an ideal mixture leads to an overestimation of the total particulate mass by up to 30% for the composition and RH range considered in the six-component system simulation. For simplified partitioning parametrizations, we suggest a modified definition of the effective saturation concentration, Cj*, by including water and other inorganics in the absorbing phase. Such a Cj* definition reduces the RH-dependency of the gas/particle partitioning of semivolatile organics in organic-inorganic aerosols by an order of magnitude as compared to the currently accepted definition, which considers the organic species only.

scholarly journals Using optical tweezing to control phase separation and nucleation near a liquid–liquid critical point

Soft Matter ◽  
2019 ◽  
Vol 15 (41) ◽  
pp. 8279-8289
Author(s):  
Finlay Walton ◽  
Klaas Wynne
Keyword(s):  
Phase Separation ◽  
Critical Point ◽  
Control Phase

Laser-induced phase separation (LIPS) and LIPS and nucleation (LIPSaN) harness fluctuations near a liquid–liquid critical point using optical tweezing and underlie the process of nonphotochemical laser-induced nucleation (NPLIN).

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