Thermodynamic Description Of Cu Research Articles

Thermodynamic description of the Cu–Pb–Sn system at the Cu–Pb side

A thermodynamic description of the ternary Cu–Pb–Sn system at the Cu–Pb side is presented. The thermodynamic parameters of the sub-systems, Cu–Pb, Cu–Sn and Pb–Sn, are taken from earlier SGTE-based assessments and those of the ternary system are optimized in this study using ternary experimental lead activity and phase equilibrium data. The present ternary description is valid for tin contents up to 60 wt%.

Thermodynamics of grain boundary premelting in alloys. I. Phase-field modeling

The rich nature of the premelting transition of grain boundaries in solid solutions is analyzed. Part I of this paper uses a multi-phase field model, whereas Part II employs atomistic Monte Carlo simulations. To enable comparison, Cu-rich Cu–Ag solid solutions are chosen for study. In the phase-field model, a system composed of two grains and a liquid phase is treated with three phase field parameters and with a realistic bulk thermodynamic description of Cu–Ag alloys obtained with the CALPHAD approach. Several different computation methods are employed, both rigorous and approximate, to examine the premelting behavior and relate it to the so-called “disjoining potential” between the solid–liquid interfaces in the grain boundary region. Depending on the grain boundary energy, temperature and grain composition chosen, several different classes of premelting transitions have been detected. As the grain concentration approaches the solidus line, one class shows a premelted layer whose thickness diverges continuously to infinity (complete wetting). Another class shows a discontinuity of the premelted layer thickness, exhibiting a first-order thin-to-thick transition prior to continuous thickening to infinity at the solidus line. In other cases, a metastable grain boundary state can exist above the solidus line, indicating the possibility of superheating/supersatuation of the grains together with the grain boundary. The possibility of such transitions has been predicted previously for generic thermodynamics by many authors. The results of the current investigation are compared with the atomistic calculations for the Cu–Ag system in Part II of this work.

Thermodynamic description of the Cu–Fe–Sn system at the Cu–Fe side

A thermodynamic description of the ternary Cu–Fe–Sn system at the Cu–Fe side is presented. The thermodynamic parameters of the sub-systems, Cu–Fe, Cu–Sn and Fe–Sn, are taken from earlier SGTE-based assessments, and those of the ternary Cu–Fe–Sn system are optimized in this study by using the experimental tin activity and phase equilibrium data. The present ternary description is valid for tin contents up to 60 wt%.

Thermodynamic description of Cu–Mg–Ni and Cu–Mg–Zn systems

A thermodynamic description is presented for ternary Cu–Mg–Ni and Cu–Mg–Zn systems. Thermodynamic parameters of binary sub-systems, Cu–Mg, Cu–Ni, Cu–Zn, Mg–Ni and Mg–Zn, are taken from earlier SGTE-based assessments and those of the Cu–Mg–Ni and Cu–Mg–Zn systems are optimized in this study using experimental phase equilibrium and thermodynamic data. Solution phases of the systems are described with the substitutional solution model and intermetallic compounds, treated as simple semi-stoichiometric phases of the (A,B) pC q type, are described with the sublattice model.

Synthesis of copper-rich amorphous alloys by computational thermodynamics

We have used thermodynamically calculated phase diagrams of Cu–Zr–Ti to identify two low-melting Cu-rich alloys denoted by A and B as bulk amorphous alloys where none were thought to exist. These alloys show greater stability of the glassy phase than previously discovered alloys in the same system, as evidenced by the critical casting diameter of 5mm. We also calculated a temperature-composition diagram for alloy A as a function of Y using an approximate thermodynamic description of Cu–Zr–Ti–Y. This diagram shows that the liquidus temperature of alloy A decreases with the addition of Y, reaches a minimum, and increases again. Our experiments indeed showed the glass-forming ability of A reaches a maximum diameter of 10mm when 2at.% Y was added and then decreases again. We thus propose that the thermodynamically calculated liquidus temperature is an excellent guide to synthesize bulkier glasses, which can be readily obtained from calculated phase diagrams.

Thermodynamic description of the Cu–Al–Ni system at the Cu–Ni side

A thermodynamic description of the ternary Cu–Al–Ni system at the Cu–Ni side is presented. The thermodynamic parameters of the sub-systems Cu–Al, Cu–Ni and Al–Ni are taken from earlier SGTE-based assessments (modifying the Al–Ni description slightly) and those of the ternary Cu–Al–Ni system and system are optimized in this study by using the experimental thermodynamic and phase equilibrium data. The present ternary description is valid at temperatures above 500 ∘C and for aluminum contents up to 18 wt%.

Thermodynamic description of the Cu–Fe–Si system at the Cu–Fe side

Thermodynamic description of the ternary Cu–Fe–Si system at the Cu–Fe side is presented. The thermodynamic parameters of the sub-systems, Cu–Fe, Cu–Si and Fe–Si, are taken from earlier SGTE-based assessments (modifying slightly the bcc description of the Fe–Si system), and those of the ternary Cu–Fe–Si system are optimized in this study by using the experimental phase equilibrium data. The present ternary description is valid for silicon contents up to 10 wt%.

Thermodynamic description of the Cu–Ni–Sn system at the Cu–Ni side

Thermodynamic description of the ternary Cu–Ni–Sn system at its Cu–Ni side is presented. The thermodynamic parameters of the binary sub-systems, Cu–Ni, Cu–Sn and Ni–Sn, are taken from earlier SGTE-based assessments (modifying the Ni–Sn description slightly) and those of the ternary Cu–Ni–Sn system are optimized in this study by using the experimental data of mixing enthalpy and phase equilibrium. The present ternary description is valid for tin contents up to 38 wt% ( x Sn≈0.25). In addition, a new description is presented for the earlier assessed Cu–P–Sn system, due to the new Cu–Sn description adopted after its appearance (and shown in the present study).

Thermodynamic description of the Cu–Mn–Ni system at the Cu–Ni side

Thermodynamic description of the ternary Cu–Mn–Ni system at its Cu–Ni side is presented. The thermodynamic parameters of the sub-systems, Cu–Mn, Cu–Ni and Mn–Ni, are taken from earlier SGTE-based assessments and those of the ternary Cu–Mn–Ni system are optimized in this study by using the experimental phase equilibrium data. The present ternary description is valid for manganese contents up to 70 wt%.