On the interfacial energy of coherent interfaces

Kaptay, George

doi:10.1016/j.actamat.2012.09.002

Cited by 53 publications

(22 citation statements)

References 48 publications

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“…The driving force and the rate of coalescence are proportional to the liquid/liquid interfacial energy. The liquid/liquid interfacial energy is proportional to the maximum of the excess Gibbs energy of mixing [24][25][26][27]. The latter, on the other hand, leads to more extended miscibility gap.…”

Section: Discussionmentioning

confidence: 99%

Effect of Y and Ni addition on liquid immiscibility in Cu–Zr–Ag ternary alloys

Janovszky

Tomolya

Svéda

et al. 2014

Journal of Alloys and Compounds

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Liquid immiscibility was studied in Cu-Zr-Ag-Y and Cu-Zr-Ag-Ni liquid alloy systems. In case of Y addition the liquid decomposes into an Ag-Y rich liquid (L 1 ) and into a Cu-Zr rich liquid (L 2 ). In case of Ni addition the separated liquid phases are Ag-rich and Cu-Zr-Ni rich liquids. Different microstructures were found as function of the volume fraction of the L 1 liquid phase. The Y addition increased the field of miscibility gap of the ternary Cu-Zr-Ag system to a greater extent compared to Ni addition. Also, the rate of coalescence of droplets in the Cu-Zr-Ag-Y system was considerably larger compared to the Cu-Zr-Ag-Ni system. These two observations are interconnected: increased miscibility means more positive excess Gibbs energy, which leads to higher liquid/liquid interfacial energy, being the driving force of coalescence. Alloys with different compositions taken from the tip of the wedge have been studied by DSC. The amorphous fraction progressively reduces when increasing the Ag-content. A small amount of amorphous phase was detected by DSC in the alloy with Ag contents of not greater than 50 at%.Keywords: Ag-Cu-Zr alloy, Liquid-liquid separation, Miscibility gap, Monotectic, Rapid solidification IntroductionCopper-zirconium (Cu-Zr) bulk metallic glasses (BMGs) have been developed due to their lower cost compared to Zr-based BMGs [1-6]. As the BMGs are quite brittle, their further development was necessary to improve their ductility, which can be achieved in three ways: either by extrinsically adding a second crystalline phase to the amorphous matrix [7] or by intrinsic phase separation [8] or by partial nanocrystallization of the amorphous matrix [9]. It is worth noting that the second phase`s shape and morphology are also very important parameters affecting mechanical properties. The second phase with sharp edges is a stress concentration site, so it reduces toughness. In contrast a spherical second phase improves the mechanical properties. The liquid phase separation meets these requirements: i. the separated phase forms spherical, generally liquid drops; ii. the liquid drops become amorphous or crystalline. In recent years such novel amorphous/amorphous [10][11][12][13] or amorphous / crystalline [14-16] composites have been synthesized.Our subject is the study of the liquid immiscibility in the Ag-Cu-Zr system, in which the homogenous liquid separates into an Ag-rich liquid (L 1 ) and into a Cu-Zr-rich liquid (L 2 ) during cooling through the miscibility gap [17][18]. In the present work nickel (Ni) and yttrium (Y) are separately added to the Ag-Cu-Zr system and their influence is studied on liquid immiscibility. These two alloying elements have been chosen to check the effect of the heat of mixing between silver (Ag) and the given element: the heat of mixing in the Ag-Y system is highly negative [19]) while that in the Ag-Ni system is positive [20].

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Section: Discussionmentioning

confidence: 99%

Effect of Y and Ni addition on liquid immiscibility in Cu–Zr–Ag ternary alloys

Janovszky

Tomolya

Svéda

et al. 2014

Journal of Alloys and Compounds

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“…All the phases/grains are assumed to be isotropic. The γ/γ′ interfacial energy calculated by Kaptay's method [51], 1.54 × 10 −6 J/cm 2 , is used in the present simulations. The detailed calculation process can be referred to our previous work [42,52].…”

Section: Calphad Coupling and Materials Parametersmentioning

confidence: 99%

A Trial to Design γ/γ′ Bond Coat in Ni–Al–Cr Mode TBCs Aided by Phase-Field Simulation

Zhang

2018

Coatings

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Phase-field modeling coupled with calculation of phase diagram (CALPHAD) database was utilized to perform a series of two-dimensional phase-field simulations of microstructure evolution in the γ + γ′/γ + γ′ Ni–Al–Cr mode bond coat/substrate systems. With the aid of phase-field simulated microstructure evolution, the relationship between the interdiffusion microstructure and the cohesiveness/aluminum protective property with different alloy compositions and bond coat thicknesses was fully discussed. A semi-quantitative tie-line selection criteria for alloy composition of the bond coat/substrate system with the identical elements, i.e., that the equilibrium Al concentrations of γ′ and γ phases in the bond coat should be similar to those in substrate, while the phase fraction of γ′ in the bond coat tends to be higher than that in the substrate, was then proposed to reduce the formation of polycrystalline structure and thermal shock from the temperature gradient.

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“…So far, the surface tension of the liquid/vapor interface was studied. A similar formalism can be extended to the interfacial energy between the liquid matrix and the dispersed nanodroplets . This will lead to the understanding of spontaneous emulsification (see below).…”

Section: Modeling the Surface Tension Of Two-component Solutionsmentioning

confidence: 99%

On the Negative Surface Tension of Solutions and on Spontaneous Emulsification

Kaptay

2017

Langmuir

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The condition of negative surface tension of a binary regular solution is discussed in this paper using the recently reconfirmed Butler equation (Langmuir 2015, 31, 5796-5804). It is shown that the surface tension becomes negative only for solutions with strong repulsion between the components. This repulsion for negative surface tension should be so strong that this phenomenon appears only within a miscibility gap, that is, in a two-phase region of macroscopic liquid solutions. Thus, for a macroscopic solution, the negative surface tension is possible only in a nonequilibrium state. However, for a nano-solution, negative surface tension is also possible in equilibrium state. It is also shown that nano- and microemulsions can be thermodynamically stable against both coalescence and phase separation. Further, the thermodynamic theory of emulsion stability is developed for a three-component (A-B-C) system with A-rich droplets dispersed in a C-rich matrix, separated by the segregated B-rich layer (the solubility of B is limited in both A and C while the mutual solubility of A and C is neglected). It is shown that when a critical droplet size is achieved by forced emulsification, it is replaced by spontaneous emulsification and the droplet size is reduced further to its equilibrium value. The existence of maximum temperature of emulsion stability is shown. Using low-energy emulsification below this maximum temperature, spontaneous emulsification can appear, which is enhanced with further decrease of temperature. This finding can be applied to interpret the experimental observations on spontaneous emulsification or for the design of stable micro- and nanoemulsions.

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On the interfacial energy of coherent interfaces

Cited by 53 publications

References 48 publications

Effect of Y and Ni addition on liquid immiscibility in Cu–Zr–Ag ternary alloys

Effect of Y and Ni addition on liquid immiscibility in Cu–Zr–Ag ternary alloys

A Trial to Design γ/γ′ Bond Coat in Ni–Al–Cr Mode TBCs Aided by Phase-Field Simulation

On the Negative Surface Tension of Solutions and on Spontaneous Emulsification

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