Association Model for Liquid Alloys

1982 ◽  
Vol 19 ◽  
Author(s):  
Ferdinand Sommer
Keyword(s):  
Large Deviations ◽  
Temperature Dependence ◽  
Physical Significance ◽  
Liquid Alloys ◽  
Association Model ◽  
Compound Formation ◽  
Regular Behavior ◽  
Good Accordance ◽  
Experimental Values ◽  
Miscibility Gaps

ABSTRACTThe concentration and the temperature dependence of thermodynamic mixing functions of liquid alloys with compound formation tendency, which often exhibit large deviations from a regular behavior, can be calculated according to an association model using only a few parameters which have a definite physical significance. The results obtained for binary and ternary alloy melts with one ore more, simultaneously occurring, binary or ternary associates are in good accordance with the experimental values. For the calculation of phase diagrams, the association model enables a correct extrapolation into concentration and temperature regions for which no experimental results are available. The occurrence and the borderline of miscibility gaps in liquid alloys with strong compound forming tendency can be quantitatively described.

Thermoelectric Power of the Liquid Sn—Te Alloy

1982 ◽  
Vol 37 (10) ◽  
pp. 1127-1131 ◽  
Author(s):  
D. H. Kurlat ◽  
M. Rosen
Keyword(s):  
Thermoelectric Power ◽  
Hard Sphere ◽  
Stoichiometric Composition ◽  
Band Model ◽  
Liquid Alloys ◽  
Sphere Approximation ◽  
The Difference ◽  
Predicted Values ◽  
Experimental Values ◽  
Two Band Model

The Seebeck coefficient (S) of Sni1-x- Tex liquid alloys was measured as a function of concentration and temperature. For 0 ≦ x <0.45 the behaviour is metallic; S values are small and negative, rising linearly with temperature. The predicted values of Ziman's theory when using the hard sphere approximation disagree with the experimental ones. The change in sign occurs for 0.45. For x = 0.5 (stoichiometric composition) the thermoelectric power decreases linearly with temperature. This fact is explained assuming a two-band model. For x ≧ 0.6 the liquid alloy becomes more semiconducting and presents a maximum in the isotherms of S for x = 0.65. For the excess tellurium concentration range we have calculated the difference EF - EV and γ/kB, assuming a S(1/T) law. The experimental values are compared with those of Dancy and Glazov.

Temperature dependence of heats of vaporization, saturated vapour pressures and cohesive energies for a group of amines

1979 ◽  
Vol 44 (12) ◽  
pp. 3521-3528 ◽  
Author(s):  
Vladimír Majer ◽  
Václav Svoboda ◽  
Josef Koubek ◽  
Jiří Pick
Keyword(s):  
Temperature Dependence ◽  
Saturated Vapour ◽  
Temperature Dependences ◽  
Experimental Values ◽  
Cohesive Energies ◽  
Heats Of Vaporization

The temperature dependences of heats of vaporization of propylamine, isopropylamine, butylamine, isobutylamine, sec-butylamine, cyclohexylamine, diethylamine and triethylamine and saturated vapour pressures of butylamine, isobutylamine, sec-butylamine and triethylamine were measured. The cohesive energies of amines studied in dependence on temperature were calculated from the experimental values.

Miscibility Gaps in Fused Salts Note VIII. Mixtures Formed by LiF and two Alkali Bromides

1975 ◽  
Vol 30 (6-7) ◽  
pp. 821-824
Author(s):  
G. Flor ◽  
Ch. Margheritis ◽  
C. Sinistri
Keyword(s):  
Temperature Field ◽  
High Temperature ◽  
Critical Temperature ◽  
Large Deviations ◽  
Alkali Metals ◽  
Ternary Systems ◽  
Fused Salts ◽  
Miscibility Gaps

Abstract Demixing phenomena were studied in 12 mixtures type LiF + (MeI, MeII)Br, MeI and MeII being alkali metals. Previous measurements of the LL equilibria in the system LiF + CsBr were extended to the high temperature field to evaluate the position of the point of maximum. Moreover, the data obtained on the system LiF + NaBr were analyzed in order to calculate the critical temperature of the "submerged" gap. The results allowed to test the thermodynamic theories concerning the reciprocal ternary systems in the case of large deviations from ideality.

Evaluation of Low-Temperature Properties and the Fragility of Asphalt Binders with Non-Arrhenius Viscosity–Temperature Dependence

2005 ◽  
Vol 1901 (1) ◽  
pp. 44-51 ◽  
Author(s):  
Huachun Zhai ◽  
Delmar Salomon
Keyword(s):  
Temperature Dependence ◽  
Asphalt Binders ◽  
Arrhenius Behavior ◽  
Direct Tension ◽  
Different Temperatures ◽  
Rotational Viscosity ◽  
Liquid Fragility ◽  
The Difference ◽  
Critical Cracking Temperature ◽  
Experimental Values

Rotational viscosities of different asphalt binders were determined at temperatures between 80°C and 185°C. Viscosity–temperature dependence of asphalt binders was described with the use of the Vogel–Tammann–Fulcher (VTF) and the William–Landel–Ferry (WLF) equations. The Vogel temperature ( Tv) and the glass transition temperature ( Tg) for different asphalt binders were determined by fitting experimental values of viscosity at different temperatures with these two equations. For asphalt binders, the difference between Tv and Tg was about 40K. Effects of asphaltenes, aging, chemical modification, and polymer content on these temperatures were evaluated. As asphaltene content increased, both temperatures, Tv and Tg, increased. Different polymers showed different effects on these temperatures. The values of Tv and Tg were correlated with the critical cracking temperature ( Tcr) determined through use of a bending beam rheometer and a direct tension tester. The results suggested that the correlations between Tv, Tg, and Tcr could be used to determine Tcr from the rotational viscosity results tested at high temperature. With simple rotational measurements, a quick estimation of Tcr of asphalt binders could be obtained. Liquid fragility theory was also used to study Tg of asphalt binders. Parameters determined with the VTF and WLF equations indicated that asphalt binders behaved as fragile liquids because of their non-Arrhenius behavior in the temperature range studied.

CALCULATION OF THE CRYSTAL FIELD IN CeZn2

1996 ◽  
Vol 10 (29) ◽  
pp. 1471-1476
Author(s):  
MIRCEA ANDRECUT
Keyword(s):  
Rare Earth ◽  
Intermetallic Compound ◽  
Electric Field ◽  
Temperature Dependence ◽  
Least Squares ◽  
Crystal Field ◽  
Crystalline Electric Field ◽  
Experimental Values ◽  
Good Agreement ◽  
Rare Earth Intermetallic

The temperature dependence of the second-order crystalline electric field (CEF) parameters of rare earth intermetallic compound CeZn 2 was deduced from the least-squares nonlinear fit to the reciprocal paramagnetic susceptibility along principal crystalline axes. The results of the calculation are in good agreement with the experimental values.

Density and Surface Tension of Fe-Cu Melts

2020 ◽  
Vol 992 ◽  
pp. 545-550
Author(s):  
Vladimir V. Vyukhin ◽  
O.A. Chikova ◽  
Ksenya Yu. Shmakova
Keyword(s):  
Surface Tension ◽  
Temperature Dependence ◽  
Cast Steel ◽  
Liquid Alloys ◽  
Humid Atmosphere ◽  
Damping Characteristics ◽  
Metal Melts ◽  
Cu Alloys ◽  
Two Phases ◽  
Large Machine

Fe-Cu alloys are used as structural materials for manufacture of large machine parts subjected to shock loads. Fe-Cu alloys have a higher corrosion resistance in a humid atmosphere and in salt solutions than cast steel. Fe-Cu alloys have high enough damping characteristics. Upon cooling the Fe-Cu melts is stratified into two phases before crystallization which in field of gravity are separated by density. It is possible to suppress delamination and obtain a material with structure of a “frozen emulsion” by heating melt to the temperature T* determined for each composition by a specific way. In this paper, we studied surface tension of liquid alloys of Fe-1wt.% Cu, Fe-20wt.% Cu, and Fe-30wt.%Cu in order to determine the temperature T*. For the melt of Fe-20wt.% Cu value T*=1670°C is highest. It is confirmed by results of measuring temperature dependence of surface tension. Temperature dependence of the surface tension Fe-Cu melts is characterized by a positive value of the temperature coefficient of surface tension dσ/dT which is abnormal for metal melts. Experimental data on the density, the surface tension of Fe-Cu liquid alloys have of independent metrological importance for practical foundry.

scholarly journals Energetics and local order in In-based liquid alloys

BIBECHANA ◽  
2015 ◽  
Vol 13 ◽  
pp. 60-71
Author(s):  
RP Koirala ◽  
BP Singh ◽  
IS Jha ◽  
D Adhikari
Keyword(s):  
Thermodynamic Properties ◽  
Local Order ◽  
Heat Of Mixing ◽  
Liquid Alloys ◽  
Association Model ◽  
Long Wavelength ◽  
Energy Of Mixing ◽  
Self Association ◽  
Free Energy Of Mixing ◽  
Solution Behaviour

A comparative study has been carried out to understand the concentration dependence of thermodynamic properties such as, free energy of mixing, heat of mixing, entropy of mixing, activity  and microscopic properties, such as concentration fluctuation in long wavelength limit  and Warren-Cowley short range order parameter  of  In-based three liquid alloys (In-Pb , In-Tl and In-Zn) on the basis of self-association model. The analysis reveals that self-association model successfully explains the observed properties of the liquid alloys.  Positive deviation of the thermodynamic properties of the alloys from the Raoultian solution behaviour indicates that the alloys are weakly segregating in nature. The comparative assessment of the interaction energy and the microscopic properties suggests that the degree of segregation is greatest in In-Zn alloy and comparable in In-Pb and In-Tl alloys.BIBECHANA 13 (2016) 60-71

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