Liquid phase separation of Co–Cu alloys in the metastable miscibility gap

2005 ◽  
Vol 413-414 ◽  
pp. 509-513 ◽  
Author(s):  
M. Kolbe ◽  
J.R. Gao
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Miscibility Gap ◽  
Cu Alloys

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.

Microstructure Formation and Nanoindentation Behavior of Rapidly Solidified Cu-Fe-Zr Immiscible Alloys

2020 ◽  
Vol 993 ◽  
pp. 39-44
Author(s):  
Xiao Jun Sun ◽  
Jie He ◽  
Jiu Zhou Zhao
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Secondary Phase ◽  
Atomic Ratio ◽  
Liquid Phase Separation ◽  
Miscibility Gap ◽  
Rapidly Solidified ◽  
Liquid Liquid Phase Separation ◽  
Zr Alloy ◽  
Liquid Miscibility Gap

The binary Cu-Fe system is characterized by a metastable liquid miscibility gap. WhenZr is added into the Cu-Fe alloy, the miscibility gap can be extended into Cu-Fe-Zr ternary system. In the present study Cu-Fe-Zr alloys were prepared by single-roller melting-spinning method, and the samples were characterized by the SEM, EDS, HRTEM and nanoidentation. The results show that liquid-liquid phase separation into CuZr-rich and FeZr-rich liquids takes place during rapid cooling the Cu-Fe-Zr alloy, and the mechanism depends on the atomic ratio of Cu to Fe. With increasing Zr content, the size of secondary phase formed by the liquid-liquid phase separation reduces to nanoscale. The structure with amorphous Cu-rich nanoparticles embedded in the amorphous Fe-rich matrix was obtained in the as-quenched Cu20Fe20Zr60 alloy. For its structure particularity of the Cu20Fe20Zr60 sample, mechanical evaluation was carried out by using nanoindentation.

Liquid–liquid phase separation in undercooled Co–Cu alloys

2002 ◽  
Vol 325 (1-2) ◽  
pp. 503-510 ◽  
Author(s):  
C.D Cao ◽  
G.P Görler ◽  
D.M Herlach ◽  
B Wei
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Cu Alloys ◽  
Liquid Liquid Phase Separation

Thermodynamics and liquid phase separation in the Cu–Co–Nb ternary alloys

2010 ◽  
Vol 25 (9) ◽  
pp. 1706-1717 ◽  
Author(s):  
Yan Yu ◽  
Xingjun Liu ◽  
Zhipeng Jiang ◽  
Cuiping Wang ◽  
Ryosuke Kainuma ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Cooling Rate ◽  
Liquid Phase Separation ◽  
Ternary Alloys ◽  
Miscibility Gap ◽  
X Ray Diffraction ◽  
Metastable Liquid ◽  
Microstructural Morphology ◽  
Work First

This work first deals with the effect of Nb addition on the liquid phase separation in the Cu–Co system, which displays a metastable liquid miscibility gap. The isothermal sections at 800, 900, 1000, 1100, and 1200 °C in the Cu–Co–Nb system have been experimentally determined by optical microscopy, electron probe microanalysis, and x-ray diffraction on the equilibrated alloys, and the phase equilibria in the Cu–Co–Nb ternary system were thermodynamically assessed by using CALPHAD (Calculation of Phase Diagrams) method on the basis of the presently determined experimental data. Nb additions can stabilize the metastable liquid phase separation in the Cu–Co binary system and significantly increase its critical temperature. The solidified Cu–Co–Nb alloys appearing on the top-bottom separated microstructural morphology under low cooling rate while forming core-type macrostructural morphology under high cooling rate have been confirmed.

Liquid Phase Separation and Dual Glassy Structure Formation of Designed Zr-Ce-Co-Cu Alloys

2016 ◽  
Vol 849 ◽  
pp. 100-106
Author(s):  
Zhong Yuan Wang ◽  
Jie He ◽  
Bai Jun Yang ◽  
Hong Xiang Jiang ◽  
Jiu Zhou Zhao ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Metallic Glasses ◽  
Atomic Ratio ◽  
Liquid Phase Separation ◽  
Miscibility Gap ◽  
Immiscible Alloys ◽  
Immiscible System ◽  
New Strategy ◽  
Fast Quenching

Development of liquid-phase separated bulk metallic glasses is retarded due to difficulties in finding of immiscible systems with high glass-forming ability (GFA) of coexistent liquids. Zr-Ce alloy is a typical liquid immiscible system characterized by a liquid miscibility gap. We added Co and Cu into the Zr-Ce immiscible system and optimized the composition of the designed Zr-Ce-Co-Cu immiscible alloys. The solidification experiments were carried out for the quaternary alloys. The result indicates that the melt separated into ZrCo-rich and CeCu-rich liquids upon cooling through the miscibility gap. By optimizing the relative atomic ratio of Co:Cu, the coexistent ZrCo-rich and CeCu-rich liquids automatically assembled eutectic compositions during the liquid-liquid phase separation (LLPS). Under the condition of fast quenching, the two liquids subsequently undergo liquid-to-glass transition, resulting in the formation of composite structure with two glasses in the samples. We successfully developed phased-separated metallic glasses based on the Zr-Ce-Co-Cu immiscible alloys. This work not only strengthens the understanding in the LLPS but also provides a new strategy on the design of the dual glassy composites.

Liquid phase separation, solidification and phase transformations of Gd–Ti and Gd–Ti–Al–Cu alloys

Calphad ◽  
2014 ◽  
Vol 44 ◽  
pp. 21-25 ◽  
Author(s):  
S. Schmitz ◽  
H.-G. Lindenkreuz ◽  
W. Löser ◽  
B. Büchner
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Phase Transformations ◽  
Liquid Phase Separation ◽  
Cu Alloys

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

2010 ◽  
Vol 10 (5) ◽  
pp. 12497-12561 ◽  
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 the phase diagram. 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, C*j, by including water and other inorganics in the absorbing phase. Such a C*j 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.

Sign in / Sign up

Export Citation Format

Share Document