Thermodynamic assessment of the Cu-Ti-Zr system. II. Cu-Zr and Ti-Zr systems

Abstract

The thermodynamic assessment of the Cu-Zr and Ti-Zr systems is carried out using the CALPHAD method. The Gibbs energy of Cu-Zr liquid alloys is described by the ideal associated solution model. The excess Gibbs energy of Ti-Zr liquid alloys and Cu-Zr and Ti-Zr solid solutions is descried by models with Redlich-Kister polynomials. The Gibbs energy of Cu-Zr intermetallic compounds is described by models taking into account their formation enthalpy and entropy. A set of self-consistent parameters of the models is obtained using data on phase equilibria and thermodynamic properties of the phases. The calculated phase diagrams of the systems and values of thermodynamic properties of the phases are in good agreement with experimental information. The relative thermodynamic stability of supercooled liquid alloys and competitive crystal phases of the Cu-Zr system are analyzed.

Thermodynamic assessment of the Cu-Ti-Zr system. III. Cu-Ti-Zr system

“…Comparing the results of our previous calculations for a number of glass-forming binary systems (Ni−(Ti, Zr, Hf) [28]; (Co, Ni, Cu)−(Ti, Zr, Hf) [29,30]; Cu−Ti [10]; Cu−Zr [21]; Cu−Hf [33]) with known concentration range of amorphization has shown that it is advisable to be guided by the relative position of metastable liquidus lines of terminal solid solutions and position of corresponding It was shown in [21] and [33] for the Cu−Zr and Cu−Hf systems, respectively, that the concentration range for the formation of bulk amorphous alloys could be correctly predicted as a concentration interval between the metastable liquidus lines at glass transition temperature.…”

“…The parameters of models describing the thermodynamic properties of phases in the boundary binary systems are taken in accordance with our previous thermodynamic assessments: Cu−Ti [20], Cu−Zr, and Ti−Zr [21]. To describe the ternary Cu−Ti−Zr system, it was needed to model the properties of ternary nonstoichiometric phases: solid solutions based on pure components, liquid phase, binary intermetallic compounds for which homogeneity regions were found in the ternary system, and ternary intermetallide τ 1 .…”

“…This conclusion is not surprising since it is shown in [27] that the contribution of ternary interaction to the mixing enthalpy of liquid Cu−Ti−Zr alloys is sign-changing and its absolute value is small. Therefore, we used only parameters of the formation of binary associates obtained in [20,21] in further calculations within the thermodynamic description of ternary melts.…”

Computational Study of Mobilities and Diffusivities in bcc Ti-Zr and bcc Ti-Mo Alloys

“…The thermodynamic parameters for the Ti-Zr and Ti-Mo binary systems are taken from the assessment of Turchanin et al [15] and Shim et al, [16] respectively. The mobility parameters for the self-diffusion coefficients of bcc Ti and bcc Zr are taken from our earlier papers on the mobilities of Ti-V [9] and Nb-Zr [17] binary systems, respectively.…”

“…The calculated Ti-Zr phase diagram according to the thermodynamic assessment of Turchanin et al [15] is given in Fig. 1.…”