ChemInform Abstract: Thermodynamics/Calorimetry. Thermodynamics of Liquid and Undercooled Liquid Al—Cu—Ni—Si Alloys.

Abstract

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On the Tendency of Solutions to Tend Toward Ideal Solutions at High Temperatures

“…However, it is mentioned [34] that other previous publications [35,36] indicate more negative heat of mixing values. Apparently, these previous works are closer to reality, as proved by recent measurements of the Sommer group [37,38] and supported also by a CALPHAD assessment. [39] If these previous [35,36] and recent [37,38] data are used for heat of mixing in combination with the activity data given in Ref.…”

Thermodynamic activities in silicon binary melts

“…The thermodynamic properties of Si-Cu melts have been studied by calorimetry technique [31][32][33]. Activities in these melts have also been measured using emf technique [34] and Knudsen-cell mass spectrometry [35,36].…”

Prediction of the Mixing Enthalpies of the Al-Cu-Ni-Zr Quaternary Alloys by the Molecular Interaction Volume Model

“…In Figure 1, a large deviation of DH pre can be observed in a range of Fig. 1-Comparison of the predicted values with experimental data of binary systems: (a) Al-Cu at 1467 K, [13] (b) Al-Ni at 1700 K, [13] (c) Al-Zr at 2045 K, [14] (d) Cu-Ni at 1473 K, [15] (e) Cu-Zr at 1485 K, [16] and (f) Ni-Zr at 1565 K. [17] x = 0.4 to 0.6, where there is a strong interaction between unlike atoms. From Reference 18, the coordination number in amorphous alloys was so large (e.g., Z = 17) that some clusters with Z may be formed in those systems.…”

“…For the Al-Ni system, the only DH Ã pre can be calculated using Eq. [16] due to the lack of the partial molar infinite dilute enthalpies of Al and Ni at 1700 K. Because the infinite dilute enthalpies of Cu and Ni are positive and the mixing enthalpy as a function of concentration seems to be symmetrical, the calculated mixing enthalpies of the Cu-Ni system are coincident with those of Hultgren et al [15] at 1473 K. For the Al-Cu, Al-Zr, Cu-Zr, and Ni-Zr systems, the predicted values are not in good agreement with the experimental data, and their errors are in the range of 10 to 20 pct. This fact may be attributed to the existence of chemical short-range order, as pointed out by Stoz et al, [13] and the asymmetry of mixing enthalpy as a function of concentration.…”

“…Table III. Average Relative Error and the Average Standard Deviation of Prediction of Al-Cu-Ni at 1700 K, [19] Al-Ni-Zr at 1565 K, [20] Al-Cu-Zr at 1450, 1485, and 2010 to 2080 K, [14] and Cu-Ni-Zr at 1565 K [17] …”